Can't connect one server

Hi. I’ve been playing on HL2 RP server over a week ago, and i get connection problem error. But my friends on that server said that’s only me get that error. I though it’s okay and i’ll reconnect, but i still dont see that server. My another friend cant see that server too, but it works with “connect” command, but not with me. Need some help!

[editline]21st July 2012[/editline]

any advices?