We are having the same issue here. Sprung up yesterday, our three users are unable to sign in. Offline still works, but not an ideal situation.
We have attempted:
uninstall - reinstall,
multiple reboots,
alternative machines,
checked port availability and domain allowances,
new user accounts,
even windows updates
An incorrect password does give a prompt so I must assume there is some communication happening with the server, but I’ve tried leaving it for hours and the launcher will not get passed the screenshot originally posted here.
Its very frustrating as one of our machines was due for an unreal update which leaves us short even in offline mode. Any assistance would be very welcome! Thanks - Daniel