OIDC: after successful login redirect to login site

[barde]

Description

After setting up an OIDC and connecting it to headplane via "integrated" I cannot login via OIDC on the /admin page.

What I expect:
being able to see the headplane Web UI

What I get:
back on the login page where I can put in an API key or try the OIDC login with the same redirect again

The OIDC in use is PocketId which shows a successful login.

Headplane is running in a docker compose setup and is emitting no debug message.

Logging in with an API key works.

Headplane Version

0.6.0 and also tried next

Headscale Version

0.26