I fixed this! I went into my router's advanced settings and turned on port-triggering (not forwarding). See screens:
I'm also having the same issue, you can find my post here: https://answers.ea.com/t5/Technical-Issues/Xbox-Cannot-Join-a-Game-While-on-The-Same-Network/m-p/7460958#M10450 I gave you XP OP because you deserve it :D...cheers, jedidiah.
Exactly the same issue. I wish EA would say something about it. I dont see any benefit to the game from this network mechanic. There are tons of ways to go around it, like using vpns, mobile data etc., so there is no really a way to prevent people who would use same ip connections maliciously. It just poses problems to people like us trying to play with friends.
Using vpn is a temporary easy fix in that matter. I hope EA would try to resolve this issue in some way so we can truly enjoy the game and its content, not spend time trying to get into servers.
This is the problem and solution:
Correct me if I am wrong but this article suggests that you open up NAT filtering, this open up your firewall - i do not suggest it
