Minecraft Crashes after connecting to a multiplayer server (Vanilla 1.11.2)

The Problem is:
I can open the MC Launcher and start the Game (1.11.2)
Then I can normally choose between Singleplayer and Multiplayer.
But when the PC is connecting to the Server, Minecraft crashes and the
Launcher is opening again and says:"There's an unsolved issue" and nothing more.
(tested with the old and the new Launcher)

I hope that someone can help me!