When I connect a server I get black screen error

[SuperNov4]

Hello there.I can't join servers or single match.Game is freeze.Why this happening ? Thanks for help

[HannesC]

Just a blackscreen or do you get any crashdumps/errors? If it's the latter, screenshot the error whereas if it's the first, try alt tabbing out to the bootstrapper cmd window and typing vid_restart in it.