Have u got the port forwarding done?
@Rendeo I'm going to assume you haven't port forwarded.
To port forward, you're just going to have to look it up depending on your router. After you port forward (using your computer's IPv4 address - should be something like 192.168.blah.blah, and 7777 for port), your LMS shows your external IP address (and port) which you give your friends.
That's pretty much it, hope it works!