diff --git a/plugin/http_auth.go b/plugin/http_auth.go
index d9a7fef88..87dd2714a 100644
--- a/plugin/http_auth.go
+++ b/plugin/http_auth.go
@@ -2,6 +2,7 @@ package plugin
 
 import (
 	"context"
+	"crypto/sha256"
 	"fmt"
 	"net/http"
 	"strings"
@@ -13,6 +14,11 @@ import (
 	"golang.org/x/oauth2"
 )
 
+func init() {
+	// some servers send SHA256 instead of the RFC 7616 compliant SHA-256
+	digest.Algs["SHA256"] = sha256.New
+}
+
 // Auth is the authorization config
 type Auth struct {
 	Type, User, Password, Token string