I'm on the network of a university campus and the network administrators did something that makes MSN Messenger fail (service not available or not connected). Every port except for port 80 seems to be closed. The weird thing is, under Windows, MSN Messenger works. On two Macs (one of which is mine), it doesn't. What could be the problem? I thought that there may be some kind of proxy that is automatically detected under Windows and not under Mac OS X, but I can't seem to find evidence of that on other Windows computers. If anyone has an idea, please let me know, cause webmessenger is a pain to work with. BTW: Using the latest version (4.0.1). Other clients like aMSN and FIRE don't work either. Also disabling the firewall doesn't work.