Have you ever been able to connect to an IRC network in the past? If so, has something recently changed in your computer/network setup or have you changed location (in particular, are you behind a school/university/office network)?
If you are behind a network it's possible certain ports are being blocked. You can try using /server ice.coldfront.net:5556 since that's a non-standard IRC port that the server supports, or if you have SSL support enabled (type //echo -a $sslready to check if you're unsure) then you can try /server irc.coldfront.net:+7778