Ensure that port 113 is being forwarded through your router and that ident is active. I found that GigaIRC is now checking idents to try to eliminate spam bots. If you're not sure about how to do this, visit
PortForward.com for assistance in configuring your router.
Aside from that, without the error/disconnect message(s), there's nothing more that I can suggest at this time.
I was able to connect to both of those networks without any problem.