[Temporary Workaround Found] Unable to login in-game
THE TEAL CYAN BANNER LIES! P.S. SMB is still bad. If you are new to this thread, read this entire OP for more.
This link will take you to a proper guide on how todo the workaround.
Also, should have prob edited this in earlier, but @[DE]Glen has already commented on this thread; says that a fix is coming soon (prob Monday if I had to guess)
2nd EDIT: It has been identified that you can disable SMB after you login.
Just to be exact, the Workstation service has to be running before starting the launcher. I tried turning it on at the login screen and login failed. Also tried turning it off after hitting Play on the launcher. That failed too.
So in summary. Turn Workstation service on, start launcher, log in, turn Workstation service off. Enjoy the game.