cant join my friend's lobby

[F2F2]

my friend created a party-privacy:OPEN lobby and i tried to connect (only says joining and then nothing happens)
the lobby is set as privacy:OPEN but in my friend list it says "playing in a private match"

what did we do wrong

[Dss0]

F2F2 parties don't work, your friend has to be ingame for you to be able to join (also he has to have upnp enabled in his router).