Beam MP server

I am trying to create a multiplayer server, I have done everything so far but I have C.O.X panaramic WiFi, and when I go to the C.O.X login to port forward, it says to use the app, there is no option to port forward on the C.O.X router login, so I forwarded a port from my app for my PC and it shows up as an added port forward. But my friends cannot connect. It always says connection failed, I’ve read it can be a firewall issue blocking my friends PC from joining on that port? How do I let BEAMMP through the firewall if so? any tips or tricks? My last option is to use himatchi which I’ve Hurd can be unstable so I don’t want to. But idk what else to do, anyone help me?!