Read here: "My dedicated/hosted server broke after patch."
The patch haven't broken your game/server. You need to have the same game version of the client, as you have on the server. Else it will detect a version missmatch and will disconnect you.
Uninstall any mods if they don't work for you and wait for updates. The vanilla dedicated server works fine in the tests we have done.
anyone using a steamCMD install should remove +validate variable from any scripts and reinstall