Me (EU) was playing a couple games with a friend (US) just 20 minutes ago. Then Steam went down several times and after it came back online, the Backend-Error attack started for both of us, so i guess it’s a global problem.
Somethings going on with steam can’t even access forums or store.
Seems to be working again now.
After steam was back up, i launched my game, got all my bogenhafen illusions removed, restarted my game, got all my bogenhafen skins back, then my game crashed, and now i get 1127 backend errors 
Yeah just logged in, received the notification for the pig hat (which I purchased two days ago) then my melee weapons on every character were deleted.
I submitted a ticket and continuously opened and closed the game… seems to be resolved now.
As CopperBack1 said I also can’t access Steam forums.
Steam is very broken, although you may be able to launch Vermintide 2 it’s likely to be an unstable experience - would advise holding off for an hour or so.
Played again for an hour or so after it was working again, but now after restarting the game, the backend error is back. There was also a backend error 1287 popping up once, while i was just standing in the keep.