RedxSkull thanks bro it worked

ill give it a try thanks

I'm trying to play bo1 zombies with my friends and i made a server which seems to be working fine except for when my friends try and join. Me and my brother (on the same internet) are able to join but my friend and his brother (also on the the same internet) are only able to join if one of them is in the game. What i mean by that is one of them joins and can play but as soon as the other joins it kicks the other one out. Does anyone know if this is a server issue or maybe internet issue between them?