Server keeps getting "terminated"

[sir_bratwurst]

Hey guys!
I have a problem with hosting a multiplayer session on our server. When a client tries to connect to the server, you get a lot of (random?) numbers in die DOS-Window on the server with the final statement "terminated". The client just cannot join or gets the message "server unavailable". This happens in Bookng and pickup mode. I've got the same problem when I try to host a game on my gamimg rig.The Server runs on Windows Server 2012 and my rig on Win 7 (64 bit). This problem started with die RC of AC 1.0.

Does anybody has a workaround or something?