[Help ASAP] Server keeps crashing

I’m encountering a problem with my server today i have came on and I play for 5-30 mins and then I it freezes and looking in web console it says

STEAMAUTH: Client xxx failure code 6
Saving player data: xxxxx
Dropped xxx from server (Client left game (Steam auth ticket has been canceled)

any help on fixing this it is starting to annoy me

This happens when your Client looses the Connection to Steam.
Try to restart your PC or call your ISP

In general is it happening to everyone on the server and the same time it will just freeze and the game server will go and down