hostedPlayerDidAccept not being called when a player accept my invitation

I have implemented in my GKMatchmakerViewControllerDelegate the method hostedPlayerDidAccept but when I present the viewcontroller and invite a friend and he accept, I can see him connected in the GameCenter interface but hostedPlayerDidAccept is never being called.

I don't really understand why it's not called/

hostedPlayerDidAccept not being called when a player accept my invitation
 
 
Q