windows 8 metro application http client hatası

 
  public static async Task<JsonArray> LoadRemoteDataAsync() 
          { 
              var client = new HttpClient(); 
              client.MaxResponseContentBufferSize = 1024 * 1024; // Read up to 1 MB of data 
   
              var response = await client.GetAsync(new Uri("https://api.foursquare.com/v2/users/self?oauth_token=XXXXXXX")); 
   
              var result = await response.Content.ReadAsStringAsync(); 
              var jarr = JsonArray.Parse(result); 
              return jarr; 
          }