It will attempt to automatically handle port forwarding, if this fails (it will say "unable to open port"), you may need to setup a "fake-lan" with something like Hamachi or Tunngle, then have everyone connect to the fake-LAN and use (fake)-local IP to connect to the server This method has been briefly tested, it should work but you may run into trouble.
(The same instructions for "could not open port" may be used for "UPnP Gateway not found")
Some settings on your router (or maybe computer) are not playing nice, so you'll need to go through the extra trouble of fake-LAN to host for anyone outside your LAN (unless you can figure out the settings, but I'm afraid I can't help with that, sorry :/).
Thank you for providing a clear screenshot of the problem!
Whenever the issue is easily visible like this, a screenshot is a good quick way to "describe" what's going on :)
@HellFireKoder Uhm me and my friend used hamachi but my friend couldnt join the server and in his computer f-secure blocks the multiplayers CMD
@LatteCoffee55 Ah, thanks!
This is addressed in the main post though...
Some settings on your router (or maybe computer) are not playing nice, so you'll need to go through the extra trouble of fake-LAN to host for anyone outside your LAN (unless you can figure out the settings, but I'm afraid I can't help with that, sorry :/).
Thank you for providing a clear screenshot of the problem!
Whenever the issue is easily visible like this, a screenshot is a good quick way to "describe" what's going on :)
@Verdnan it should have
Does your router have upnp enabled? Have you tried opening the ports manually?
@HellFireKoder this