Cannot connect to Blitz servers

I have no trouble at all getting into Crossfire matches, but I can't connect to any Blitz servers. I managed to join one yesterday, dropped the connection after about 10 minutes, and haven't been able to join a Blitz game since. I can't imagine it's my internet connection, since my web browser works just fine, and everything else on Steam works (TF2, L4D, etc). Anyone have any idea why I might be able to get into Crossfire but not Blitz?