My roommate and I have been trying to play zombies with some other friends. When one us isn't hosting, anyone can join the game fine. However, when my roommate or I host, anyone can join except the other person on the same network. We are using just regular friend joining, UPnP enabled and such. When I double click his name to join, it gives the joining game message but doesn't actually join, like the IP is wrong or somethign.
To get around the issue, when my roommate hosts I just use a VPN. This works fine, but I would prefer to not use a VPN because it can be spotty and makes the ping worse.
Any suggestions for fixing? Thanks.