Are you maybe trying to log in to the PTS by mistake?
I noticed mine just updated this morning, so maybe that is what is giving you the error?
ETA: (my launcher also defaulted to PTS this morning, which is the only reason I asked. If it did that to me, then it could happen for someone else, as well.)
I used Ctl+Alt+Delete to stop the launcher displaying Loading... and restarted the laucher - now it works and i was able to get to the game. Thanks for the help.