Bobzer

I have a problem where when I check for servers all I see is a red x with no other information. Like this: I know the server is up because I have friends playing on it and I can see it in the server browser on the Arma 2 launcher, but when I try join it from there the game freezes on "receiving from host" or something. My firewall isn't blocking Arma 2 and I remember once I was actually able to see the server. Anyone any ideas?