OIDC Error without any Information in Jellyfin Logs

[JBBERLIN77]

I get the following error message:

Error redeeming code: {"error_description":"Multiple client authentication methods found in the token request. Please note that only one client authentication method is allowed."} / no description Try logging in again.

I have actually managed to solve every ODIC problem so far, even with difficult ODIC implementations.

But I don't get an error message in the logs neither with Jellyfin nor with my SSO provider program.

We use Manageengine AD Self Service Plus as SSO/OIDC/SAML provider.

[9p4]

Can you tell Manage engine to only use one kind of authentication method?

[JBBERLIN77]

Yes you can but it would be nice to know how the Jellyfin OIDC plugin is used:

client_secret_basic or client_secret_post or client_secret_jwt

[9p4]

should be client_secret_post, afaik.