AOC Connecting Problems

[DerReinsteckFuchs]

Heyho, I've got some problems with my Aoc. All in all the whole NeoEE works but if I want to start a game in Aoc the connection window opens with the two players. The hoster has a blue checkmark and the player who joins the game gots a mikrophon and after a few seconds a tombstone with the sign "RIP". We don't know how to fix this problem and need you help
FYI: the normal EE works normal and we don't have any problems. It's just the AOC

Thank you
Tom