battle of stalingrad cannot see friend in coop/dogfight matches

[eddoe]

So I could from nowhere host games in MP but when a friend joined in coop he could not see any plane at all except his own, and when we tried dogfighting he could not spawn at all, he could shoot in the background and all the sound sounded ok he could hear when he was firing, hear the engine and when he crashes but when he tries to respawn it just says "already spawned"...... been trying for more or less 4 hours to try different things but there is literally no solution anywhere at all but this seems like a common problem aswell is the only solution to refund this this game? Would rather not but it is so frustrating that it doesn't work at all.

[-DED-Rapidus]

It looks like you don't pass UDP packets from your server to the client.

Please see the link how port forwarding is performed: