diff --git a/backend/open_webui/utils/auth.py b/backend/open_webui/utils/auth.py
index c8c1f1372..9befaf2a9 100644
--- a/backend/open_webui/utils/auth.py
+++ b/backend/open_webui/utils/auth.py
@@ -228,7 +228,9 @@ def get_current_user(
             )
         else:
             if WEBUI_AUTH_TRUSTED_EMAIL_HEADER:
-                trusted_email = request.headers.get(WEBUI_AUTH_TRUSTED_EMAIL_HEADER)
+                trusted_email = request.headers.get(
+                    WEBUI_AUTH_TRUSTED_EMAIL_HEADER, ""
+                ).lower()
                 if trusted_email and user.email != trusted_email:
                     # Delete the token cookie
                     response.delete_cookie("token")