I create a lobby with 2 private slots (SSFIVAE) and invite 2 friends to play against me, but after the first one joins the other one cannot connect. We see him joining, but his connection bar is grey and his "Benchmark" is E (this is only available in the PC edition). After about 5 seconds he leaves because he "cannot connect" to my lobby.
It does not matter who joins first, we have tried both ways and both can connect to my lobby one at a time.
How can we play together in one lobby?