title: Gamecenter Matchmaking Doesn't Work
body: <p>Here is my Menu.m's onEnter method:</p>
  
  <pre><code>GKMatchRequest *request = [[[GKMatchRequest alloc] init] autorelease];
  request.minPlayers = 2;
  request.maxPlayers = 2;
  GKMatchmakerViewController *mmvc = [[[GKMatchmakerViewController alloc] initWithMatchRequest:request] autorelease];
  mmvc.matchmakerDelegate = self;
  
  tempVC = [[UIViewController alloc] init];
  [[[CCDirector sharedDirector] view] addSubview:tempVC.view];
  [tempVC presentModalViewController: mmvc animated: NO];
  mmvc.view.frame = CGRectMake(150, 150, 510, 420);
  </code></pre>
  
  <p>I tried with device and simulator but they couldn't match.</p>
  
  <p>I also tried it to do by following Ray Wenderlich's <a href="http://www.raywenderlich.com/3276/how-to-make-a-simple-multiplayer-game-with-game-center-tutorial-part-12" rel="nofollow">tutorial</a>:</p>
  
  <p>But then, even matchmakerviewcontroller didn't show up. I don't know what I'm doing wrong.</p>
  
  <p>Thanks in advance.</p>