Discourse Integration Nextcloud bad csrf

On my Desktop I tried the setup with Mozilla Firefox running on windows 8. Also tried with updated Brave on my Android 11.
From my perspective nothing changed on the client side.

I see that content:

With Brave, nothing happens when I click “Genehmigen”
With Mozilla Firefox I get this window


So both lead nowhere.

With Brave on Android 11 I get the Bad CSRF Error