Then you must have missed a step, mostoften the XMPP settings ( external URL:5222 to One-X Portal port forwarding )
You can check from a separate internet connection and try to telnet to the URL port 5222 towards the One-X Portal server, if it connects then the network setup is ok, if it fails then something in the network setup is wrong.
If a telnet connection is successful then examine the One-X Portal logs to see were it fails.