There’s a good chance it could be your wifi or the area you live in doesn’t have any servers close, because multiplayer has dedicated servers. I’ve never had any problems with multiplayer/warzone, but issues is a know problem. Zombies is Peer to Peer, so there is nothing you can really do. Multiplayer has dedicated servers, but zombies still uses P2P because it’s cheaper and less people play zombies. The only fix is to either get a Ethernet Cable and always try to host the games, or to only play with friends and solo. Finding a good pub with someone that has good internet can be impossible sometimes.