We’re aware of the crash with that error. The VAC ban, though, it is unheard of.
Just to check a few things first just in case: could you try to do a full clean reinstall of the game, and unsubscribe from any mods if you have installed any?
We contacted privately the users affected and we resolved this inquiry there.
Please remember that there are also options to disable VAC and BattlEye on private servers, and that there could be problems trying to join a server hosted in your own machine. To override that, the server need to be launched with -nosteam in the command line, or follow the steps we posted in this thread: