Nextcloud 17 - MacOs client loop login, browser login loop

after I updated my docker-compose installation from nextcloud 16 to nextcloud 17 I habe serious issues to login into my Admin account.
When I try to login via Browser, there is no redirect to my data, a simple manual page refresh and everything is fine. But when I want to login with the MacOS Desktop app the loading circle does one round after another but nothing happen. Even tried to login with auth-code. My Android mobile app is not affected by this issue and works fine. I updated the desktop app, but with no change. The side shows in dev-view : Error: Content Security Policy (translated) the settings of the page blocked loading of resource http://nextcloud…/login/v2/grant (form-action)

I solved it. My nextcloud instance was behind a traefik reverse proxy, so in the config.php of nextcloud i had to add the ‘overwriteprotocol’ => ‘https’, line
so now all works fine

If someone has the same error.