Can't see all the player Zombie BO2

[Erosth]

Hi, i got a friend with whom we play in Zombie BO2.
We all downloaded the game the same way and did the same manipulation.

But the thing is he can't see all the players, he can only see 1-2-3 players depending on how many we are on the server.

We checked the files, unistalled and redownloaded it n check some topics online but got nothing that matched up.

Does anyone know how can we make it so he can see all the players.

Thanks :).