Draug13

Finally I was able to join custom games, or at least get to the lobbys. Once there i was able to connect to anyone in the lobby without any problems but when someone was joining lobby after me they were not able to connect to myself at all (and all of them had nickname PlayerName), tried that at least dozen of times and result was always the same so at the end i was not able to play even 1 game because i was sooner or later kicked out from lobby. All ports open as per Monks

I have the same problem so you are not alone wiith it.