if you can join it from a LAN pc then check the ports are setup correctly for the Server pc with your Router or Software firewall, or both if you have both.

The setting you are looking for in the web admin for your router will be something like:

Virtual Server
Port Forwarding


They will have simmilar options to these depending on the maker

Public Port - Start
Public Port - End
Private Port
Port Type
Host IP Address

1. Public Port - Start is the first port you need to set for FL so enter 2300
2. Public Port - End enter the same 2300
3. Private Port - you guessed it the same again 2300
4. Port Type - enter TCP
5. Host IP Address - enter the LAN IP of the Server pc, to find it from the Startbar / Run type cmd then type ipconfig , the IP address is the figure you enter
6. repeat 1 too 5 for 2301 too 2305

Then find the save option, usually it's in the same window as the reboot option and finally reboot your router.

Next bit will depend on your Software firewall, you will need to enter all those again in it so no firewall setup is generic like routers so cant advise much beyond reading the manual.