fixes

Author: GitTimeraider

app/routes.py

@@ -905,7 +905,10 @@ def oidc_login():
         oauth = OAuth(current_app)
 
         # Register the OIDC client
-        client_kwargs = {'scope': 'openid profile email'}
+        client_kwargs = {
+            'scope': 'openid profile email',
+            'token_endpoint_auth_method': 'client_secret_post'  # Send credentials in POST body instead of header
+        }
 
         # Check if using discovery or manual endpoints
         if oidc_config.discovery_endpoint and oidc_config.discovery_endpoint.strip():
@@ -991,7 +994,10 @@ def oidc_callback():
         use_manual = session.get('oidc_use_manual', False)
 
         # Register the OIDC client (same as in login)
-        client_kwargs = {'scope': 'openid profile email'}
+        client_kwargs = {
+            'scope': 'openid profile email',
+            'token_endpoint_auth_method': 'client_secret_post'  # Send credentials in POST body instead of header
+        }
 
         if not use_manual and oidc_config.discovery_endpoint and oidc_config.discovery_endpoint.strip():
             # Try discovery endpoint