Jochi,

I just believe that you know your diverse firewalls and how to let the game through them. Atm I've no idea what the problem could be. Can you host with a vanilla version of MTW-VI without traces of beta_8 anywhere else?

Apart from that, we had some similar problems on sunday. The games of those of us who usually host (meaning it has worked 100s of times before) were invisible. It wasn't just the beta_8 games but all games in the lobby. There's one guy who reported 6 games total when I was only able to see 2 of them and others couldn't see any. Relogging or switching back and forth between the "Internet games" screen and the lobby wasn't any help.
In the end it worked again but there was no indication on what the problem was.

R'as