App does not support leaderboards - iMessage App

I have an iMessage app, and trying to get Leaderboard scores. I am getting error:

Error Domain=GKErrorDomain Code=3 "The requested operation could not be completed due to an error communicating with the server." UserInfo={GKServerStatusCode=5043, NSLocalizedDescription=The requested operation could not be completed due to an error communicating with the server., NSUnderlyingError=0x600000ed3960 {Error Domain=GKServerErrorDomain Code=5043 "status = 5043, MyApp does not support leaderboards" UserInfo={GKServerStatusCode=5043, NSLocalizedFailureReason=status = 5043, MyApp does not support leaderboards}}}

Please note that my app is live, game center is enabled and it has been days since leaderboards were created on iTunes Connect.

func getScoreLeaderboard(leaderboardIdentifier:String, completion:@escaping ((_ resultScore:GKScore?) -> Void)) {

    let leaderBoardRequest = GKLeaderboard()

    leaderBoardRequest.identifier = leaderboardIdentifier

    leaderBoardRequest.loadScores {

        (resultGKScore, error) in

        guard error == nil && resultGKScore != nil else {

            completion(nil)

            return

        }

        completion(leaderBoardRequest.localPlayerScore)

    }

}

I have a doubt, but not sure it can be the problem. Problem might be:

I have an iMessage app with Bundle ID e.g. com.mygame. On iTunes Connect, I made a test app to check in app purchase issue encountered. And its Bundle ID is com.mygame.MessagesExtension.

I think that it is trying to get Leaderboard from app with extension bundle ID. Can it be possible? Since my app com.mygame is live, I am unable to delete extension test app, though it is not being used.

Any help is appreciated.

I confirm that Leaderboard was being retrieved from test app instead of actual one. I end up implementing scores management via Firebase instead of Game Center. Apple customer services are pathetic.