Forza Horizon 4 Can't proceed without logging in?

As soon as I start Forza Horizon 4, the login window appears briefly, but it is empty and closes immediately, whereupon Forza says, "You can't continue without a profile login". I've already tried a few things, reinstalled Xbox Live services, reset MS Store, checked proxy settings, but it still doesn't work, so I hope someone who has / had the same problem can help me.

Any controllers attached? If so, everyone will hang out

I had it connected, but it doesn't work without it either, I restarted my PC before.