I make a game and it perfectly connects with multiplayer but on the same computer or same network but I can’t connect with another computer/network.
It’s completely normal.
Presuming the game or project is in the testing or initial phase of development, Set the region in the Photon Server Settings which you can find at:
Assets > Photon > PhotonUnityNetworking > Resources.
Change the Fixed region option with -
"in". Photon connects players in the same region.
If that doesn’t help you can make some changes and create and join the room with one player, print its room name in the console. Make an option to feed the room name to join the room for the other player and they will connect.
For a more advanced way, before joining or creating a room, create an option to look for available rooms via room listing and join that room.