I just tested the game today (Uber Launcher) and I can connect to UberNet just fine. The server I'm using is US Central. What server are you trying to connect to?
Server region only affect where games you created hosted, but login/lobby point that same for everyone.
Uber might have multiple servers in backend, but likely it's US. Though I just want to tell that region selection in settings can't affect authentication. E.g if you have some problem with creating/joining actual games then it's might be related to server region you try to connect to.