diff --git a/app/gramps_mcp_server/client.py b/app/gramps_mcp_server/client.py
index 394bd2c..908187d 100644
--- a/app/gramps_mcp_server/client.py
+++ b/app/gramps_mcp_server/client.py
@@ -45,7 +45,7 @@ class GrampsWebClient:
     def _login(self) -> None:
         """Authentifizierung bei GrampsWeb und Token-Speicherung."""
         login_endpoints = [
-            ("/api/token/", "form"),
+            ("/api/token/", "json"),
             ("/api/login/", "json"),
         ]
         for path, mode in login_endpoints: