Почему не видит GetRespons приложение windows phone?

string address = "http://kladr-api.ru/api.php?query=";
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(address);
                request.Method = "GET";
                request.Timeout = 10000;
                request.Accept = "application/json";
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                var stream = new StreamReader(response.GetResponseStream());