Players on Steam have been experiencing a Splitgate "Unable To Authenticate" error that is stopping them from playing. But, we have the solution to fix that authentication error and get you back into the fight.
Splitgate Unable To Authenticate Fix
The reason behind the Splitgate unable to authenticate error is an issue with the Steam client, rather than the game itself.
To resolve it, all you need to do is restart Steam by shutting it down or restarting your computer, just to be extra sure the client has shut down.
From there, boot Steam back up and open Splitgate again, which should allow you to play, with no authentication error.
If the problem does persist, give this method a few more tries, otherwise, you will need to contact Splitgate's support or give it a few hours to see if the problem has been fixed.