Connection Wizard is looping between "Log in" and "Grant access"

[xotox91]

That could be the reverse proxy. I had the same problem. The solution for me was to add the ‘overwriteprotocol’ variable to config.php and set it to “https”. See: server/config/config.sample.php at master · nextcloud/server · GitHub

Unfortunately, I ran directly into the next problem with it:

NextCloud 15: desktop client version 2.3.3.1 works, meanwhile 2.5.x doesn't work

Now we are running nextcloud 15.0.2 and login users via SAMLv2 with a universities federation services that redirect our login queries. The web client and the android client work correctly. But desktop client Windows and linux only work with client version 2.3.3.1, meanwhile 2.5.x don’t work. It get stuck on the grant acces page.