Undo host

[Lihaässä]

I'm hosting a mp game with a private server. During the last turn one of the players got a message "invalid cd-key" and lost his turn. Is there any way to undo last hosting? I'm using text-based hosting server with ssh - no option to use graphic user interface.

invalid cd-key issue occurs probably because he was using my second computer with same cd-key simultaneously with me.

Thanks!