Dont work game with my friend.

TnKr

A friend can't join a group after 1 game, although he seems to connect, but when choosing a game, he doesn't throw into the 1st lobby, you can't even see neither mine nor his invitations in the lobby

Linkdouken

Are you on the same platform? If you are on playstation for example, I suggest trying to join via playstation account friends list as opposed to in game - could have a better result