ILeaderboard on iOS is not working?

The bottom code is only working, when I comment the SetUserFilter() line. Like this:

     // m_Leaderboard.SetUserFilter(userIds);

But why? I want the actual score from the local user. How can I do this?

 ILeaderboard m_Leaderboard;

     ...

     string[] userIds = new string[] { Social.localUser.id };
     m_Leaderboard = Social.CreateLeaderboard();
     m_Leaderboard.id = "1";
     m_Leaderboard.SetUserFilter(userIds);

     m_Leaderboard.LoadScores ( result => {

         Debug.Log("Received " + m_Leaderboard.scores.Length + " scores");
         foreach (IScore score in m_Leaderboard.scores) {
             Debug.Log("Score: "+score);

         }

     });

What I'm doing wrong?

I've created a leaderboard on the Game Center.