Forwardujes blbe porty.
http://www.blitzkrieg.de/index.php?page=faq.us.bli tz
How can I play online if I use a firewall or router?
If you have problems connecting to Internet games when you try to play from behind a router/firewall, you have to open the following ports: Blitzkrieg Ports 8889 and 9089 Gamespy Ports 6667 (IRC) 80 (HTTP) 3783 (Voice Chat Port) 27900 (Master Server UDP Heartbeat) 28900 (Master Server List Request) 29900 (GP Connection Manager) 29901 (GP Search Manager) 13139 (Custom UDP Pings) 6500 (incoming, pre-configured port can be changed in the file "svc.cfg" in the command line "roomqueryport=