Unet- Null refernence OnMatchCreate , only on Iphone build

Whenever, i try to create a match on my iphone build , i get a null reference on OnMatchCreate call back . This doesn't seem to happen on my Andriod or Pc builds and i am able to create matches on them without any errors.

here's the code -

 public void CreateMatch(string _name, uint _size){

     CreateMatchRequest request = new CreateMatchRequest ();
     request.name = _name;
     request.size = _size;
     request.advertise = true;
     request.password = string.Empty;
     manager.matchMaker.CreateMatch (request, OnMatchCreate);
     roomSize = _size;
     manager.isHost =true;
 }

 public void OnMatchCreate(CreateMatchResponse matchResponse)
 {
     if (matchResponse.success)
     {
         Debug.Log("Create match succeeded");
         matchIsCreated = true;
         Utility.SetAccessTokenForNetwork(matchResponse.networkId, new NetworkAccessToken(matchResponse.accessTokenString));
         _matchInfo = new MatchInfo (matchResponse);
         MatchCreated = _matchInfo;
         manager.StartHost (_matchInfo);
         manager.MyMatchInfo = _matchInfo;
     }
     else
     {
         Debug.LogError ("Create match failed");
     }
 }