Erreur OIDC

[Ethsim2 (Ethan)]

That looks like the OpenID Connect (OIDC) login failing between your forum and the identity provider. I don’t have access to your server logs, but the admin can turn on verbose_auth_logs and then check /logs for the exact reason. That should show whether it’s a cookie/session mismatch, a claim mismatch, or another OIDC setting.