Error Message while connecting MCP Server with oauth2

I tried to connect our MCP Server to chatgpt with oauth2.
Everthing seems to be fine. I got my login screen from our oauth2 provider, but after adding die credentials and redirecting to the openai callback I’ve got the following error message:

Id.deserialize_from_str should only be used to deserialize strings that are already OpenAIUUIDs

Has someone an idea what’s going wrong?