Apple Game Center sandbox: players invitations work but NOT auto-match

Question

I've implemented Multi-player in my IOS game using the standard matchmaking interface screen. Everything works well if I invite another player in the sandbox : the other player receives the push notification, the game is launched etc... and we can enjoy a cool multiplayer session.

The problem is when I try to use auto-match (without inviting a specific friend). I start the game on 2 devices, launch the same standard matchmaking interface screen and click on "play now" on both. Then I wait for 5 minutes before matchmakerViewController fails with the error: "The requested operation could not be completed due to an error communicating with the server"

Does it mean auto-match doesn't work in sandbox?

Thank you for your help!

here's my code:

- (IBAction) hostMatch:(id)sender
{   
    GKMatchRequest *request = [[[GKMatchRequest alloc] init] autorelease];
    request.minPlayers = 2;
    request.maxPlayers = 2;

    GKMatchmakerViewController *mmvc = [[[GKMatchmakerViewController alloc] initWithMatchRequest:request] autorelease];
    mmvc.matchmakerDelegate = self;

    [self presentModalViewController:mmvc animated:YES];        
}

Answer 1

Not sure what your problem might be without seeing the code, but auto-match definitely works on sandbox. For me the following does the trick:

GKMatchRequest *request = [[[GKMatchRequest alloc] init] autorelease];
request.minPlayers = 2;
request.maxPlayers = 4;
GKMatchmakerViewController *mmvc = [[[GKMatchmakerViewController alloc] initWithMatchRequest:request] autorelease];
mmvc.matchmakerDelegate = self;
[self presentModalViewController:mmvc animated:YES];