Plutonium

Ok, so i fixed it. If you can't join your friend, one, follow this video:https://www.youtube.com/watch?v=GH3t5Nvn6xs&ab_channel=Raku, and two: if that doesn't work, then enter a public lobby, both of you. Then go back into lobby and join ur friend. Easy as that

Whenever i try to play with my friend on bo2 zombies, its telling us both that we are unable to join. We tried some methods, but after 20 minutes; still nothing. If their is anything that will help, please respond.