We use a standard chat port for the server, 6667 (which is often the IRC server port). Some organizations, however, don't want their users using IRC and specifically block this port. Unfortunately, if that's the case, there's nothing you can do except to contact the technical support people at your organization and ask:

I'm trying to use a chat application on a Web site that uses port 6667. Unfortunately, I can't connect. I was wondering if that port has been blocked in our firewall or proxy server configuration?

Good luck,
DocJohn