Refusal to connect to friends servers

Hey there, I followed the server set-up guide for the BeamMP mod, port forwarding, auth key, and set up. Both me and a friend attempted this however neither work. We’ve used both public and internal ipv4, ensured that it was set up with the port 30814 as well as being opened to TCP+UDP. Considering this was two different ISPs as well as my friend successfully performing port forwarding for other games previously. However, nothing thus far has worked. We are both able to direct connect to our own servers but can’t connect to each others. There is a message when launching saying

[WARN] Game is newer than recommended, multiplayer may not work as intended!

However this doesn’t seem to affect much. Does anyone know what’s going on with this?