Multiplayer using Steam Subsystem connection problem

Hey, I’m trying to develop a multiplayer game, and it works pretty well, but for some reason, sometimes I need to launch the game three times to connect to a game (I’ve tested it only by LAN connection, on the same computer), meaning that if I launch the game twice, I host the game on one client, but the other client can’t connect, but if I launch another client, it can connect to the host. Can anyone help? Thanks!

Check LogNet log whether Join succeeded or refused reason.