Having the same issue here with join with friends.
I'm using Steam and I'm unable to join with 2 others on the same network/router. 1 is on the EA app and the other is on the Steam App. 2 out of the 3 of us would be able to join the game while the other stays in the lobby. Sometimes, only 1 of us is able to join in while the other 2 are stuck in the lobby.
There are times when it would just be 2 of us, both on Steam and on the same network/router and we join but there are times when we cant. Another time, 1 is on the EA app and the other is on Steam and they could join but there are times when they cant join together.
During the BETA, 4 us would be playing together on the same router/network and we ran into this issue when 3 of us were on Steam and the other was on the EA app. The fix was us all being on Steam and we would be able to join.
All wired through the same router.
Port forwarding between all 3 computers.
We've tried uninstalling and re-installing the game and that would work but then it would stop working.
Clicked "verifying integrity of game files" and it would update saying that 3 files were updated.
On the EA App, we would "repair" the game and that would sometimes work.
Happens most of the time during peak hours, 7 PM - 10 PM PST.
Using Zipply Fiber as our network provider.
I've heard this issue has been going on since ALPHA, so why is this not a high priority?!?