How to list all available GKTurnBasedMatches for a player?

Question

I'm building a game using Game Center's turn based matches.

I want to display a list of all the available matches. I've tried using loadMatchesWithCompletionHandler(), but the array of games returns as nil, and the error also returns as nil. There are some ongoing matches.

This is what I have so far:

func authenticateLocalUser() {
    if !gameCenterAvailable { return }

    let player = GKLocalPlayer.localPlayer()
    if player.authenticated == false {
        player.authenticateHandler = {(viewController, error) -> Void in
            if viewController != nil && self.presentingViewController != nil
            {
                self.presentingViewController!.presentViewController(viewController!, animated: true, completion: {
                    GKLocalPlayer.localPlayer().registerListener(self)

                    GKTurnBasedMatch.loadMatchesWithCompletionHandler({games, error in
                        print(games)
                        if games != nil {
                            print(games!.count)
                        }else {
                            print(error)
                        }
                    })
                })
            } else {

                if player.authenticated == true {
                    GKLocalPlayer.localPlayer().registerListener(self)

                    GKTurnBasedMatch.loadMatchesWithCompletionHandler({games, error in
                        print(games)
                        if games != nil {
                            print(games!.count)
                        }else {
                            print(error)
                        }
                    })
                }
            }
        }
    } else {
        print("already authenticated")
    }
}

I even get nil when creating a new match (it will print the match I just created, though):

func findMatchWith(minPlayers: Int, maxPlayers: Int) {
    if !gameCenterAvailable { return }

    let request = GKMatchRequest()
    request.minPlayers = minPlayers
    request.maxPlayers = maxPlayers
    request.defaultNumberOfPlayers = 2

    GKLocalPlayer.localPlayer().loadFriendPlayersWithCompletionHandler({players, error in
        if error != nil {return}
        request.recipients?.append(players![0])

        GKTurnBasedMatch.findMatchForRequest(request, withCompletionHandler: { match, error in
            if error != nil {
                print(error?.localizedDescription)
                return
            }
            print(match)

            GKTurnBasedMatch.loadMatchesWithCompletionHandler({games, error in
                print(games)
                if games != nil {
                    print(games!.count)
                }else {
                    print(error?.localizedDescription)
                } 
            })
        })
    })
}

Answer 1

It wasn't the code. It was how the game was set up in iTunes Connect. I needed to do this:

1. Go to My App > App Store > Prepare for submission and toggle the switch for Game Center
2. Add a leaderboard I had previously created under "Features"

Later, I will try to delete the leaderboard, and see if it still works. The actual app won't have a leaderboard.

My confusion was because I wasn't getting the "unrecognized game" error, and I was able to create matches, play turns, list player's friends, but not list matches.