You're probably behind a router, making it unable for outsiders to access your chat-server.
Try redirecting port 1234 to your local IP if that's the case.
You should then also make sure you have the public IP address and not the local one.
Reserved (Default) Local IP's:
You can get your public IP by going to whatismyip.com.Code:10.0.0.0 - 10.255.255.255 172.16.0.0 - 172.31.255.255 192.168.0.0 - 192.168.255.255
And as I mentioned before in this thread, a guide to port forwarding.