Logging in on Unity Hub opening Firefox with empty website and nothing happens

When I start Unity Hub and click on “Sign In”, Firefox opens up with an empty website (https://api.unity.com/v1/oauth2/authorize with a lot of ?x=y parameters in the URL) and nothing else happens.

I tried several ways like killing all Unity Hub processes (also background processes with Task Manager) and deleting %AppData%/UnityHub folder and running again, but nothing of them worked :frowning:

Also, I can’t use admin rights (I don’t know the admin password)