When some of my team's members try to reach my game session with filter they had a message which say : "Connection failed", I've check my firewall and ports redirections in my router and Arma 3 is in UPnP mode so it still don't come from it, and when some others friends try to reach a session of someone else it works randomly good or bad, and for some other strange reasons it's steel working much when we looking our session in the whole server list, but not always.