IM Weirdness

Trillian pretty much won't connect at all on campus. On a whim, I tried AIM 5.9, and it connected. I checked Trillian again, won't connect. I could always get Y!M to connect since it has that "Firewall with no proxies" option that basically turns it into a web client for the service. MSN also connects if I use the real MSN.

What the fuck is Trillian doing differently that makes it not connect?