diff --git a/assets/js/components/Config/AuthConnectButton.vue b/assets/js/components/Config/AuthConnectButton.vue
index 98f1beced..65d0d287d 100644
--- a/assets/js/components/Config/AuthConnectButton.vue
+++ b/assets/js/components/Config/AuthConnectButton.vue
@@ -1,7 +1,12 @@
 <template>
 	<!-- Connect to provider button (when URL is available) -->
 	<div v-if="providerUrl" class="d-flex flex-column align-items-end gap-2">
-		<a :href="providerUrl" target="_blank" class="btn btn-primary">
+		<a
+			:href="providerUrl"
+			target="_blank"
+			class="btn btn-primary"
+			@click="$emit('external-click')"
+		>
 			{{
 				$t("authProviders.buttonConnect", {
 					provider: providerDomain,
@@ -40,7 +45,7 @@ export default defineComponent({
 		loading: { type: Boolean, default: false },
 		showHint: { type: Boolean, default: true },
 	},
-	emits: ["prepare"],
+	emits: ["prepare", "external-click"],
 	computed: {
 		providerDomain(): string | null {
 			return this.providerUrl ? extractDomain(this.providerUrl) : null;
diff --git a/assets/js/components/Config/AuthProvidersCard.vue b/assets/js/components/Config/AuthProvidersCard.vue
index 2f6fe98fa..39a91ae79 100644
--- a/assets/js/components/Config/AuthProvidersCard.vue
+++ b/assets/js/components/Config/AuthProvidersCard.vue
@@ -14,7 +14,7 @@
 				<div
 					v-for="provider in providerList"
 					:key="provider.id"
-					class="auth-provider-item d-flex align-items-baseline justify-content-between"
+					class="d-flex align-items-baseline justify-content-between mb-2"
 				>
 					<div class="d-flex align-items-baseline">
 						<span
@@ -25,7 +25,7 @@
 					</div>
 					<button
 						type="button"
-						class="btn btn-link btn-sm p-0"
+						class="btn btn-link btn-sm p-0 lh-1"
 						:class="provider.authenticated ? 'text-muted' : 'text-warning'"
 						@click="handleProviderAction(provider)"
 					>
@@ -93,8 +93,4 @@ export default defineComponent({
 .auth-providers-list {
 	width: 100%;
 }
-
-.auth-provider-item {
-	padding: 0.5rem 0;
-}
 </style>
diff --git a/assets/js/components/Config/AuthSuccessBanner.vue b/assets/js/components/Config/AuthSuccessBanner.vue
index b0363e1de..745826cdf 100644
--- a/assets/js/components/Config/AuthSuccessBanner.vue
+++ b/assets/js/components/Config/AuthSuccessBanner.vue
@@ -1,8 +1,19 @@
 <template>
-	<div class="alert alert-success my-4 pb-0" role="alert" data-testid="auth-success-banner">
-		<p>
+	<div
+		class="alert my-4 pb-0"
+		:class="isError ? 'alert-danger' : 'alert-success'"
+		role="alert"
+		:data-testid="testId"
+	>
+		<p v-if="isError">
+			<strong>{{ $t("authProviders.authorizationFailed") }}</strong
+			><br />
+			{{ errorMessage }}
+		</p>
+		<p v-else>
+			<strong>{{ $t("authProviders.authorizationSuccessful") }}</strong
+			><br />
 			{{ $t("authProviders.success", { title: providerName }) }}
-			{{ $t("authProviders.successCloseTab") }}
 		</p>
 	</div>
 </template>
@@ -14,10 +25,17 @@ import { defineComponent, type PropType } from "vue";
 export default defineComponent({
 	name: "AuthSuccessBanner",
 	props: {
-		providerId: { type: String, required: true },
+		providerId: { type: String, default: "" },
+		error: { type: String, default: "" },
 		authProviders: { type: Object as PropType<AuthProviders>, default: () => ({}) },
 	},
 	computed: {
+		isError() {
+			return !!this.error;
+		},
+		errorMessage() {
+			return this.error || "";
+		},
 		providerName() {
 			for (const [name, provider] of Object.entries(this.authProviders)) {
 				if (provider.id === this.providerId) {
@@ -26,6 +44,9 @@ export default defineComponent({
 			}
 			return "Unknown";
 		},
+		testId() {
+			return this.isError ? "auth-error-banner" : "auth-success-banner";
+		},
 	},
 });
 </script>
diff --git a/assets/js/components/Config/DeviceModal/DeviceModalBase.vue b/assets/js/components/Config/DeviceModal/DeviceModalBase.vue
index 87ad05579..8acdc089d 100644
--- a/assets/js/components/Config/DeviceModal/DeviceModalBase.vue
+++ b/assets/js/components/Config/DeviceModal/DeviceModalBase.vue
@@ -647,7 +647,7 @@ export default defineComponent({
 				const { name } = await this.device.create(this.apiData, force);
 				this.saving = false;
 				this.succeeded = true;
-				await sleep(1000);
+				await sleep(500);
 				this.$emit("added", name);
 				(this.$refs["modal"] as any).close();
 			} catch (e) {
@@ -681,7 +681,7 @@ export default defineComponent({
 				console.log("update succeeded, closing modal");
 				this.saving = false;
 				this.succeeded = true;
-				await sleep(1000);
+				await sleep(500);
 				this.$emit("updated");
 				(this.$refs["modal"] as any).close();
 			} catch (e) {
diff --git a/assets/js/components/Top/AuthProviderModal.vue b/assets/js/components/Top/AuthProviderModal.vue
index 0badb9626..fcdc219a2 100644
--- a/assets/js/components/Top/AuthProviderModal.vue
+++ b/assets/js/components/Top/AuthProviderModal.vue
@@ -4,7 +4,7 @@
 		ref="modal"
 		:title="modalTitle"
 		data-testid="auth-provider-modal"
-		@close="handleClose"
+		@closed="handleClosed"
 	>
 		<div class="container mx-0 px-0">
 			<!-- Success message after authentication -->
@@ -56,6 +56,7 @@
 						:provider-url="auth.providerUrl ?? undefined"
 						:loading="auth.loading"
 						@prepare="prepareAuthentication"
+						@external-click="waitingForAuthentication = true"
 					/>
 				</div>
 			</template>
@@ -103,7 +104,6 @@
 
 <script lang="ts">
 import { defineComponent, type PropType } from "vue";
-import Modal from "bootstrap/js/dist/modal";
 import GenericModal from "../Helper/GenericModal.vue";
 import AuthCodeDisplay from "../Config/AuthCodeDisplay.vue";
 import AuthConnectButton from "../Config/AuthConnectButton.vue";
@@ -156,9 +156,11 @@ export default defineComponent({
 		},
 	},
 	watch: {
-		provider(newProvider) {
-			if (newProvider) {
+		providerId(newId) {
+			if (newId) {
 				this.reset();
+				// auto-run the prepare step. no user input needed
+				this.prepareAuthentication();
 			}
 		},
 	},
@@ -169,12 +171,11 @@ export default defineComponent({
 			this.logoutError = null;
 			this.waitingForAuthentication = false;
 		},
-		handleClose() {
+		handleClosed() {
 			this.reset();
 		},
 		async prepareAuthentication() {
-			if (!this.providerId) return;
-			this.waitingForAuthentication = true;
+			if (!this.providerId || this.isAuthenticated) return;
 			await prepareAuthLogin(this.auth, this.providerId);
 		},
 		async performLogout() {
@@ -185,10 +186,7 @@ export default defineComponent({
 
 			const result = await performAuthLogout(this.providerId);
 			if (result.success) {
-				const modalElement = (this.$refs["modal"] as any)?.$el;
-				if (modalElement) {
-					Modal.getInstance(modalElement)?.hide();
-				}
+				(this.$refs["modal"] as any)?.close();
 			} else {
 				this.logoutError = result.error || this.$t("authProviders.logoutFailed");
 			}
diff --git a/assets/js/views/Config.vue b/assets/js/views/Config.vue
index d14c998b5..572a1bac8 100644
--- a/assets/js/views/Config.vue
+++ b/assets/js/views/Config.vue
@@ -8,8 +8,9 @@
 			/>
 			<div class="wrapper pb-5">
 				<AuthSuccessBanner
-					v-if="callbackCompleted"
+					v-if="callbackCompleted || callbackError"
 					:provider-id="callbackCompleted"
+					:error="callbackError"
 					:auth-providers="authProviders"
 				/>
 				<WelcomeBanner v-if="loadpointsRequired" />
@@ -563,6 +564,9 @@ export default defineComponent({
 		callbackCompleted() {
 			return this.$route.query["callbackCompleted"] as string | undefined;
 		},
+		callbackError() {
+			return this.$route.query["callbackError"] as string | undefined;
+		},
 		authProviders() {
 			return store.state?.authProviders;
 		},
diff --git a/i18n/de.json b/i18n/de.json
index e44d4eb91..678543e68 100644
--- a/i18n/de.json
+++ b/i18n/de.json
@@ -2,7 +2,9 @@
   "authProviders": {
     "authCode": "Autorisierungscode",
     "authCodeHelp": "Kopiere diesen Code und verwende ihn im nächsten Schritt. Gültig für {duration}.",
+    "authorizationFailed": "Autorisierung fehlgeschlagen",
     "authorizationRequired": "Autorisierung erforderlich",
+    "authorizationSuccessful": "Autorisierung erfolgreich",
     "buttonConnect": "Mit {provider} verbinden",
     "buttonDisconnect": "Trennen",
     "confirmLogout": "Sicher, dass du {title} trennen möchtest?",
@@ -12,7 +14,7 @@
     "logoutFailed": "Abmeldung fehlgeschlagen",
     "modalDescriptionLogin": "Schließe die Autorisierung ab, um eine Verbindung mit {provider} herzustellen.",
     "modalDescriptionLogout": "Dies trennt dein {provider}-Konto und entfernt den Zugriff auf dessen Daten.",
-    "success": "Die Autorisierung mit {title} war erfolgreich.",
+    "success": "{title} ist jetzt verbunden und einsatzbereit.",
     "successCloseModal": "Du kannst diesen Dialog jetzt schließen.",
     "successCloseTab": "Du kannst diesen Tab jetzt schließen.",
     "title": "Autorisierungsstatus"
diff --git a/i18n/en.json b/i18n/en.json
index 72fde60b1..572c812fe 100644
--- a/i18n/en.json
+++ b/i18n/en.json
@@ -2,7 +2,9 @@
   "authProviders": {
     "authCode": "Authentication Code",
     "authCodeHelp": "Copy this code and use it in the next step. Valid for {duration}.",
+    "authorizationFailed": "Authorization Failed",
     "authorizationRequired": "Authorization Required",
+    "authorizationSuccessful": "Authorization Successful",
     "buttonConnect": "Connect to {provider}",
     "buttonDisconnect": "Disconnect",
     "confirmLogout": "Are you sure you want to disconnect {title}?",
@@ -12,7 +14,7 @@
     "logoutFailed": "Failed to logout",
     "modalDescriptionLogin": "Complete the authorization process to establish connection with {provider}.",
     "modalDescriptionLogout": "This will disconnect your {provider} account and remove access to its data.",
-    "success": "Authorization with {title} was successful.",
+    "success": "{title} is now connected and ready to use.",
     "successCloseModal": "You can now close this dialog.",
     "successCloseTab": "You can now close this tab.",
     "title": "Authorization Status"
diff --git a/plugin/auth/demo.go b/plugin/auth/demo.go
index a3764a545..5aec084da 100644
--- a/plugin/auth/demo.go
+++ b/plugin/auth/demo.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"net/url"
+	"strings"
 	"time"
 
 	"github.com/evcc-io/evcc/api"
@@ -17,43 +18,53 @@ func init() {
 }
 
 type demo struct {
-	token  *oauth2.Token
-	region string
-	method string
+	token       *oauth2.Token
+	server      string
+	method      string
+	redirectUri string
+	onlineC     chan<- bool
 }
 
 var demoInstance *demo
 
 func NewDemoFromConfig(_ context.Context, other map[string]any) (oauth2.TokenSource, error) {
 	var cc struct {
-		Region string
-		Method string
+		Server      string
+		Method      string
+		RedirectUri string
 	}
 
 	if err := util.DecodeOther(other, &cc); err != nil {
 		return nil, err
 	}
 
-	return NewDemo(cc.Region, cc.Method)
+	return NewDemo(cc.Server, cc.Method, cc.RedirectUri)
 }
 
-func NewDemo(region string, method string) (oauth2.TokenSource, error) {
+func NewDemo(server string, method string, redirectUri string) (oauth2.TokenSource, error) {
 	// reuse instance (similar to oauth.go getInstance pattern)
 	if demoInstance != nil {
 		// update existing instance with new values
-		demoInstance.region = region
+		demoInstance.server = server
 		demoInstance.method = method
+		demoInstance.redirectUri = redirectUri
 		return demoInstance, nil
 	}
 
 	demoInstance = &demo{
-		region: region,
-		method: method,
+		server:      server,
+		method:      method,
+		redirectUri: redirectUri,
 	}
 
-	if _, err := providerauth.Register("demo", demoInstance); err != nil {
+	onlineC, err := providerauth.Register("demo", demoInstance)
+	if err != nil {
 		return nil, err
 	}
+	demoInstance.onlineC = onlineC
+
+	// Send initial auth status
+	demoInstance.onlineC <- false
 
 	return demoInstance, nil
 }
@@ -65,41 +76,63 @@ func (o *demo) Token() (*oauth2.Token, error) {
 	return o.token, nil
 }
 
-func (o *demo) Login(_ string) (string, *oauth2.DeviceAuthResponse, error) {
-	// Simulate error for ERROR region
-	if o.region == "ERROR" {
-		return "", nil, fmt.Errorf("region not supported")
+func (o *demo) Login(state string) (string, *oauth2.DeviceAuthResponse, error) {
+	// Validate server URL has proper scheme
+	if !strings.HasPrefix(o.server, "http://") && !strings.HasPrefix(o.server, "https://") {
+		return "", nil, fmt.Errorf("server must start with http:// or https://")
 	}
 
-	// For demo, immediately authenticate without requiring external flow
-	o.token = &oauth2.Token{
-		AccessToken: "demo-token",
-		Expiry:      time.Now().Add(24 * time.Hour),
+	// Validate redirect URI has proper scheme
+	if !strings.HasPrefix(o.redirectUri, "http://") && !strings.HasPrefix(o.redirectUri, "https://") {
+		return "", nil, fmt.Errorf("redirectUri must start with http:// or https://")
 	}
 
-	// TODO use network settings after https://github.com/evcc-io/evcc/pull/25141
-	uri := "http://localhost:7070/providerauth/callback"
+	// Build mock login URL with state and redirectUri (complete callback URL)
+	values := url.Values{}
+	values.Set("state", state)
+	values.Set("redirectUri", o.redirectUri)
+
+	mockLoginURL := fmt.Sprintf("%s/mock-login?%s", o.server, values.Encode())
 
 	if o.method == "device-code" {
 		// Device code flow: URI comes from DeviceAuthResponse
 		return "", &oauth2.DeviceAuthResponse{
 			UserCode:        "12AB345",
-			VerificationURI: uri,
+			VerificationURI: mockLoginURL,
 			Expiry:          time.Now().Add(10 * time.Minute),
 		}, nil
 	}
 
 	// Redirect flow: URI in first return value
-	return uri, nil, nil
+	return mockLoginURL, nil, nil
 }
 
 func (o *demo) Logout() error {
 	o.token = nil
+	if o.onlineC != nil {
+		o.onlineC <- false
+	}
 	return nil
 }
 
 func (o *demo) HandleCallback(params url.Values) error {
-	// no-op: token already set in Login()
+	// Extract code from callback parameters
+	code := params.Get("code")
+	if code == "" {
+		return fmt.Errorf("missing code parameter")
+	}
+
+	// Create token based on code (for demo, we use a fixed token)
+	o.token = &oauth2.Token{
+		AccessToken: code, // Use the code as the access token
+		Expiry:      time.Now().Add(24 * time.Hour),
+	}
+
+	// Notify that authentication succeeded
+	if o.onlineC != nil {
+		o.onlineC <- true
+	}
+
 	return nil
 }
 
@@ -108,5 +141,5 @@ func (o *demo) Authenticated() bool {
 }
 
 func (o *demo) DisplayName() string {
-	return "demo"
+	return "Demo Auth"
 }
diff --git a/server/providerauth/handler.go b/server/providerauth/handler.go
index ccd9adff9..511d54b4f 100644
--- a/server/providerauth/handler.go
+++ b/server/providerauth/handler.go
@@ -152,20 +152,23 @@ func (a *Handler) handleLogout(w http.ResponseWriter, r *http.Request) {
 	jsonWrite(w, "OK")
 }
 
+func (a *Handler) redirectToError(w http.ResponseWriter, r *http.Request, message string) {
+	http.Redirect(w, r, "/#/config?callbackError="+url.QueryEscape(message), http.StatusFound)
+}
+
 func (a *Handler) handleCallback(w http.ResponseWriter, r *http.Request) {
 	q := r.URL.Query()
 
 	if q.Has("error") {
-		w.WriteHeader(http.StatusBadRequest)
-		fmt.Fprintf(w, "error: %s: %s\n", q.Get("error"), q.Get("error_description"))
+		errorMsg := q.Get("error") + ": " + q.Get("error_description")
+		a.redirectToError(w, r, errorMsg)
 		return
 	}
 
 	encryptedState := q.Get("state")
 	state, err := DecryptState(encryptedState, a.secret)
 	if err != nil || !state.Valid() {
-		w.WriteHeader(http.StatusBadRequest)
-		fmt.Fprintf(w, "invalid state")
+		a.redirectToError(w, r, "invalid state")
 		return
 	}
 
@@ -175,15 +178,13 @@ func (a *Handler) handleCallback(w http.ResponseWriter, r *http.Request) {
 	// Find the corresponding provider
 	id, ok := a.states[encryptedState]
 	if !ok {
-		w.WriteHeader(http.StatusBadRequest)
-		fmt.Fprintf(w, "no provider found for state")
+		a.redirectToError(w, r, "no provider found for state")
 		return
 	}
 
 	provider, ok := a.providers[id]
 	if !ok {
-		w.WriteHeader(http.StatusInternalServerError)
-		fmt.Fprintf(w, "internal provider state unexpected")
+		a.redirectToError(w, r, "internal provider state unexpected")
 		return
 	}
 
@@ -193,8 +194,7 @@ func (a *Handler) handleCallback(w http.ResponseWriter, r *http.Request) {
 	// Handle the callback
 	if err := provider.HandleCallback(r.URL.Query()); err != nil {
 		a.log.ERROR.Printf("callback for provider %s failed: %v", id, err)
-		w.WriteHeader(http.StatusInternalServerError)
-		fmt.Fprintln(w, "callback failed")
+		a.redirectToError(w, r, "callback failed")
 		return
 	}
 
diff --git a/tests/config-device-auth-demo.tpl.yaml b/tests/config-device-auth-demo.tpl.yaml
index e5af390d7..46e3395e7 100644
--- a/tests/config-device-auth-demo.tpl.yaml
+++ b/tests/config-device-auth-demo.tpl.yaml
@@ -6,18 +6,25 @@ products:
       en: Auth Demo Meter
 auth:
   type: demo
-  params: ["region", "method"]
+  params: ["server", "method", "redirectUri"]
 params:
   - name: usage
     choice: ["grid"]
-  - name: region
+  - name: server
     description:
-      generic: Region
-    choice: ["EU", "US", "CN", "ERROR"]
+      generic: Server
+    default: "http://localhost:7072"
+    required: true
+  - name: redirectUri
+    description:
+      generic: Redirect URI
+    example: "http://localhost:7070/providerauth/callback"
+    required: true
   - name: method
     description:
       generic: Authentication Method
     choice: ["redirect", "device-code"]
+    required: true
   - name: power
     description:
       generic: Power
diff --git a/tests/config-device-auth.spec.ts b/tests/config-device-auth.spec.ts
index 2c11013de..ef40e382c 100644
--- a/tests/config-device-auth.spec.ts
+++ b/tests/config-device-auth.spec.ts
@@ -1,6 +1,7 @@
 import { test, expect } from "@playwright/test";
 import { start, stop, restart, baseUrl } from "./evcc";
 import { enableExperimental, expectModalVisible, expectModalHidden } from "./utils";
+import { simulatorUrl, startSimulator, stopSimulator } from "./simulator";
 
 test.use({ baseURL: baseUrl() });
 
@@ -12,11 +13,18 @@ const templateFlags = [
   "tests/config-device-auth-demo.tpl.yaml",
 ];
 
+// Build complete redirect URI with callback path
+function getRedirectUri(url: string): string {
+  return new URL(url).origin + "/providerauth/callback";
+}
+
 test.beforeEach(async () => {
+  await startSimulator();
   await start(undefined, undefined, templateFlags);
 });
 test.afterEach(async () => {
   await stop();
+  await stopSimulator();
 });
 
 test.describe("config device auth", async () => {
@@ -35,25 +43,55 @@ test.describe("config device auth", async () => {
     await meterModal.getByLabel("Manufacturer").selectOption("Auth Demo Meter");
 
     // step 1: auth view
-    await expect(meterModal.getByLabel("Region")).toBeVisible();
+    await expect(meterModal.getByLabel("Server")).toBeVisible();
+    await expect(meterModal.getByLabel("Redirect URI")).toBeVisible();
     await expect(meterModal.getByLabel("Authentication Method")).toBeVisible();
     await expect(meterModal.getByLabel("Power")).not.toBeVisible();
     await expect(meterModal.getByRole("button", { name: "Validate & save" })).not.toBeVisible();
     await expect(meterModal.getByRole("button", { name: "Save" })).not.toBeVisible();
-    await meterModal.getByLabel("Region").selectOption("EU");
+    await meterModal.getByLabel("Server").fill(simulatorUrl());
+    await meterModal.getByLabel("Redirect URI").fill(getRedirectUri(page.url()));
     await meterModal.getByLabel("Authentication Method").selectOption("redirect");
     await meterModal.getByRole("button", { name: "Prepare connection" }).click();
-    await expect(meterModal.getByRole("link", { name: "Connect to localhost" })).toBeVisible();
-    await expect(meterModal.getByLabel("Authentication Code")).not.toBeVisible();
 
-    // we dont navigate to localhost, just trigger ui update because demo auth state is already established
-    await page.evaluate(() => {
-      document.dispatchEvent(new Event("visibilitychange"));
-    });
+    // Get the login link and remove target="_blank" to keep it in same page
+    const loginLink = meterModal.getByRole("link", { name: "Connect to localhost" });
+    await expect(loginLink).toBeVisible();
+    await loginLink.evaluate((el) => el.removeAttribute("target"));
+    await loginLink.click();
 
-    // step 2: show regular device form
-    await expect(meterModal.getByLabel("Region")).toHaveValue("EU");
-    await expect(meterModal.getByLabel("Authentication Method")).toHaveValue("redirect");
+    // Wait for navigation to mock login page
+    await page.waitForLoadState("networkidle");
+
+    // Click login button on mock page - use evaluate to ensure JS executes
+    const loginButton = page.getByRole("button", { name: "Login Successfully" });
+    await expect(loginButton).toBeVisible();
+    await loginButton.evaluate((btn: HTMLButtonElement) => btn.click());
+
+    // Wait for redirect back to config page
+    await page.waitForURL(/.*\/#\/config.*/);
+
+    // Verify success banner appears
+    const successBanner = page.getByTestId("auth-success-banner");
+    await expect(successBanner).toBeVisible();
+    await expect(successBanner).toContainText("Authorization Successful");
+    await expect(successBanner).toContainText("Demo Auth is now connected and ready to use");
+
+    // After successful auth, reopen the meter modal to continue configuration
+    await page.getByRole("button", { name: "Add grid meter" }).click();
+    await expectModalVisible(meterModal);
+    await meterModal.getByLabel("Manufacturer").selectOption("Auth Demo Meter");
+
+    // step 2: show regular device form - auth is complete, fill in server details again
+    await meterModal.getByLabel("Server").fill(simulatorUrl());
+    await meterModal.getByLabel("Redirect URI").fill(getRedirectUri(page.url()));
+    await meterModal.getByLabel("Authentication Method").selectOption("redirect");
+
+    // Even though auth is already done, still need to click prepare connection to proceed to device fields
+    await meterModal.getByRole("button", { name: "Prepare connection" }).click();
+    await page.waitForTimeout(500);
+
+    // Now the Power field should be visible since auth is already complete
     await expect(meterModal.getByLabel("Power")).toBeVisible();
     await meterModal.getByLabel("Power").fill("5000");
     await expect(meterModal.getByRole("button", { name: "Validate & save" })).toBeVisible();
@@ -70,7 +108,7 @@ test.describe("config device auth", async () => {
     // re-open meter for editing
     await page.getByTestId("grid").getByRole("button", { name: "edit" }).click();
     await expectModalVisible(meterModal);
-    await expect(meterModal.getByLabel("Region")).toHaveValue("EU");
+    await expect(meterModal.getByLabel("Server")).toHaveValue(simulatorUrl());
     await expect(meterModal.getByLabel("Authentication Method")).toHaveValue("redirect");
     await expect(meterModal.getByLabel("Power")).toHaveValue("5000");
     await expect(meterModal.getByRole("button", { name: "Prepare connection" })).not.toBeVisible();
@@ -82,10 +120,10 @@ test.describe("config device auth", async () => {
     await restart(undefined, templateFlags);
     await page.reload();
 
-    // re-open meter for editing after restart, auth status as to be reestablished
+    // re-open meter for editing after restart, auth status has to be reestablished
     await page.getByTestId("grid").getByRole("button", { name: "edit" }).click();
     await expectModalVisible(meterModal);
-    await expect(meterModal.getByLabel("Region")).toHaveValue("EU");
+    await expect(meterModal.getByLabel("Server")).toHaveValue(simulatorUrl());
     await expect(meterModal.getByLabel("Authentication Method")).toHaveValue("redirect");
     await expect(meterModal.getByLabel("Power")).not.toBeVisible();
     // note: prepare connection step is auto-executed, since all required fields are already present
@@ -104,7 +142,8 @@ test.describe("config device auth", async () => {
     await meterModal.getByLabel("Manufacturer").selectOption("Auth Demo Meter");
 
     // select device-code method
-    await meterModal.getByLabel("Region").selectOption("EU");
+    await meterModal.getByLabel("Server").fill(simulatorUrl());
+    await meterModal.getByLabel("Redirect URI").fill(getRedirectUri(page.url()));
     await meterModal.getByLabel("Authentication Method").selectOption("device-code");
     await meterModal.getByRole("button", { name: "Prepare connection" }).click();
 
@@ -115,7 +154,7 @@ test.describe("config device auth", async () => {
     await expect(meterModal.getByRole("link", { name: "Connect to localhost" })).toBeVisible();
   });
 
-  test("error region shows auth error", async ({ page }) => {
+  test("error server shows auth error", async ({ page }) => {
     await page.goto("/#/config");
     await enableExperimental(page, true);
 
@@ -123,18 +162,141 @@ test.describe("config device auth", async () => {
     const meterModal = page.getByTestId("meter-modal");
     await expectModalVisible(meterModal);
     await meterModal.getByLabel("Manufacturer").selectOption("Auth Demo Meter");
-    await meterModal.getByLabel("Region").selectOption("ERROR");
+    await meterModal.getByLabel("Server").fill("invalid-url-without-scheme");
+    await meterModal.getByLabel("Redirect URI").fill(getRedirectUri(page.url()));
     await meterModal.getByLabel("Authentication Method").selectOption("redirect");
     await meterModal.getByRole("button", { name: "Prepare connection" }).click();
 
-    await expect(meterModal).toContainText("region not supported");
+    await expect(meterModal).toContainText("server must start with http:// or https://");
     await expect(meterModal.getByRole("button", { name: "Prepare connection" })).toBeVisible();
     await expect(meterModal.getByRole("link", { name: "Connect to localhost" })).not.toBeVisible();
     await expect(meterModal.getByLabel("Authentication Code")).not.toBeVisible();
     await expect(meterModal.getByLabel("Power")).not.toBeVisible();
 
     // clear error on input change
-    await meterModal.getByLabel("Region").selectOption("EU");
-    await expect(meterModal).not.toContainText("region not supported");
+    await meterModal.getByLabel("Server").fill(simulatorUrl());
+    await expect(meterModal).not.toContainText("server must start with http:// or https://");
+
+    // test invalid redirect URI
+    await meterModal.getByLabel("Redirect URI").fill("invalid-redirect");
+    await meterModal.getByRole("button", { name: "Prepare connection" }).click();
+
+    await expect(meterModal).toContainText("redirectUri must start with http:// or https://");
+    await expect(meterModal.getByRole("button", { name: "Prepare connection" })).toBeVisible();
+    await expect(meterModal.getByRole("link", { name: "Connect to localhost" })).not.toBeVisible();
+    await expect(meterModal.getByLabel("Authentication Code")).not.toBeVisible();
+    await expect(meterModal.getByLabel("Power")).not.toBeVisible();
+
+    // clear error on input change
+    await meterModal.getByLabel("Redirect URI").fill(getRedirectUri(page.url()));
+    await expect(meterModal).not.toContainText("redirectUri must start with http:// or https://");
+  });
+
+  test("user denies authorization shows error banner", async ({ page }) => {
+    await page.goto("/#/config");
+    await enableExperimental(page, true);
+
+    // create a grid meter with auth
+    await page.getByRole("button", { name: "Add grid meter" }).click();
+    const meterModal = page.getByTestId("meter-modal");
+    await expectModalVisible(meterModal);
+    await meterModal.getByLabel("Manufacturer").selectOption("Auth Demo Meter");
+    await meterModal.getByLabel("Server").fill(simulatorUrl());
+    await meterModal.getByLabel("Redirect URI").fill(getRedirectUri(page.url()));
+    await meterModal.getByLabel("Authentication Method").selectOption("redirect");
+    await meterModal.getByRole("button", { name: "Prepare connection" }).click();
+
+    // Get the login link and remove target="_blank" to keep it in same page
+    const loginLink = meterModal.getByRole("link", { name: "Connect to localhost" });
+    await expect(loginLink).toBeVisible();
+    await loginLink.evaluate((el) => el.removeAttribute("target"));
+    await loginLink.click();
+
+    // Wait for navigation to mock login page
+    await page.waitForLoadState("networkidle");
+
+    // Click deny button on mock page
+    const denyButton = page.getByRole("button", { name: "Deny Access" });
+    await expect(denyButton).toBeVisible();
+    await denyButton.evaluate((btn: HTMLButtonElement) => btn.click());
+
+    // Wait for redirect back to config page (first goes through callback, then to config)
+    await page.waitForURL(/.*\/#\/config.*callbackError.*/);
+
+    // Wait for the error banner to appear
+    const errorBanner = page.getByTestId("auth-error-banner");
+    await expect(errorBanner).toBeVisible();
+    await expect(errorBanner).toContainText("access_denied: User denied authorization");
+  });
+
+  test("authorization card connect and disconnect flow", async ({ page }) => {
+    await page.goto("/#/config");
+    await enableExperimental(page, true);
+
+    // create a grid meter with auth and prepare connection
+    await page.getByRole("button", { name: "Add grid meter" }).click();
+    const meterModal = page.getByTestId("meter-modal");
+    await expectModalVisible(meterModal);
+    await meterModal.getByLabel("Manufacturer").selectOption("Auth Demo Meter");
+    await meterModal.getByLabel("Server").fill(simulatorUrl());
+    await meterModal.getByLabel("Redirect URI").fill(getRedirectUri(page.url()));
+    await meterModal.getByLabel("Authentication Method").selectOption("redirect");
+    await meterModal.getByRole("button", { name: "Prepare connection" }).click();
+
+    // verify connection link is ready but close modal instead of clicking it
+    await expect(meterModal.getByRole("link", { name: "Connect to localhost" })).toBeVisible();
+    await meterModal.getByRole("button", { name: "Close" }).click();
+    await expectModalHidden(meterModal);
+
+    // check that authorization card appeared with Demo Auth entry
+    const authCard = page.getByTestId("auth-providers");
+    await expect(authCard).toBeVisible();
+    await expect(authCard).toContainText("Demo Auth");
+    const connectButton = authCard.getByRole("button", { name: "Connect" });
+    await expect(connectButton).toBeVisible();
+
+    // click connect button and verify auth provider modal opens
+    await connectButton.click();
+    const authModal = page.getByTestId("auth-provider-modal");
+    await expectModalVisible(authModal);
+    const loginLink = authModal.getByRole("link", { name: "Connect to localhost" });
+    await expect(loginLink).toBeVisible();
+
+    // complete authentication flow
+    await loginLink.evaluate((el) => el.removeAttribute("target"));
+    await loginLink.click();
+
+    // wait for navigation to mock login page
+    await page.waitForLoadState("networkidle");
+
+    // click login button on mock page
+    const loginButton = page.getByRole("button", { name: "Login Successfully" });
+    await expect(loginButton).toBeVisible();
+    await loginButton.evaluate((btn: HTMLButtonElement) => btn.click());
+
+    // wait for redirect back to config page
+    await page.waitForURL(/.*\/#\/config.*/);
+
+    // verify card still exists and Demo Auth now shows disconnect button
+    await expect(authCard).toBeVisible();
+    await expect(authCard).toContainText("Demo Auth");
+    const disconnectButton = authCard.getByRole("button", { name: "disconnect" });
+    await expect(disconnectButton).toBeVisible();
+
+    // click disconnect and verify modal contents
+    await disconnectButton.click();
+    await expectModalVisible(authModal);
+    await expect(authModal).toContainText("Demo Auth");
+    const confirmDisconnectButton = authModal.getByRole("button", { name: "disconnect" });
+    await expect(confirmDisconnectButton).toBeVisible();
+
+    // confirm disconnect
+    await confirmDisconnectButton.click();
+    await expectModalHidden(authModal);
+
+    // verify card still exists and Demo Auth shows connect button again
+    await expect(authCard).toBeVisible();
+    await expect(authCard).toContainText("Demo Auth");
+    await expect(authCard.getByRole("button", { name: "Connect" })).toBeVisible();
   });
 });
diff --git a/tests/simulator/api.ts b/tests/simulator/api.ts
index 4938b89b7..ae8f105f4 100644
--- a/tests/simulator/api.ts
+++ b/tests/simulator/api.ts
@@ -135,6 +135,16 @@ const updateOcppState = () => {
   }));
 };
 
+const demoAuthMiddleware = (
+  _req: Connect.IncomingMessage,
+  _res: ServerResponse,
+  next: Connect.NextFunction
+) => {
+  // Mock login requests are now handled by the Vue app
+  // This middleware is kept for potential future extensions
+  next();
+};
+
 const ocppMiddleware = (
   req: Connect.IncomingMessage,
   res: ServerResponse,
@@ -213,6 +223,7 @@ export default () => ({
       server.middlewares.use(openemsMiddleware);
       server.middlewares.use(teslaloggerMiddleware);
       server.middlewares.use(shellyMiddleware);
+      server.middlewares.use(demoAuthMiddleware);
       server.middlewares.use(ocppMiddleware);
     };
   },
diff --git a/tests/simulator/src/Simulator.vue b/tests/simulator/src/Simulator.vue
index 22e5fe698..cfb9f5c57 100644
--- a/tests/simulator/src/Simulator.vue
+++ b/tests/simulator/src/Simulator.vue
@@ -1,6 +1,25 @@
 <template>
+	<!-- Mock Login View -->
+	<div v-if="mockLoginMode" class="container" style="max-width: 400px; margin-top: 5rem">
+		<div class="alert alert-info mb-4">
+			<strong>Mock External Login Page</strong>
+			<p class="mb-0">This simulates an external OAuth provider login screen.</p>
+		</div>
+
+		<h1 class="mb-4">Select Action</h1>
+
+		<button type="button" class="btn btn-success w-100 mb-3" @click="mockLogin('demo-token')">
+			Login Successfully
+		</button>
+
+		<button type="button" class="btn btn-danger w-100 mb-3" @click="mockDeny()">
+			Deny Access
+		</button>
+	</div>
+
+	<!-- Regular Simulator View -->
 	<form
-		v-if="state"
+		v-else-if="state"
 		class="container"
 		style="max-width: 500px; margin-bottom: 8rem"
 		@submit.prevent="save"
@@ -338,6 +357,9 @@ export default defineComponent({
 	name: "Simulator",
 	data() {
 		return {
+			mockLoginMode: false,
+			mockLoginState: "",
+			mockLoginRedirectUri: "",
 			state: null as {
 				site: {
 					grid: { power: number };
@@ -362,9 +384,33 @@ export default defineComponent({
 		};
 	},
 	mounted() {
-		this.load();
+		this.checkMockLoginMode();
+		if (!this.mockLoginMode) {
+			this.load();
+		}
 	},
 	methods: {
+		checkMockLoginMode() {
+			const urlParams = new URLSearchParams(window.location.search);
+			const state = urlParams.get("state");
+			const redirectUri = urlParams.get("redirectUri");
+
+			if (state && redirectUri) {
+				this.mockLoginMode = true;
+				this.mockLoginState = state;
+				this.mockLoginRedirectUri = redirectUri;
+			}
+		},
+		mockLogin(code: string) {
+			const callbackUrl = `${this.mockLoginRedirectUri}?state=${this.mockLoginState}&code=${code}`;
+			console.log("Redirecting to:", callbackUrl);
+			window.location.href = callbackUrl;
+		},
+		mockDeny() {
+			const callbackUrl = `${this.mockLoginRedirectUri}?state=${this.mockLoginState}&error=access_denied&error_description=User denied authorization`;
+			console.log("Redirecting to:", callbackUrl);
+			window.location.href = callbackUrl;
+		},
 		async save() {
 			await axios.post("/api/state", this.state);
 		},