从IClo​​udAPI获取联系人列表

通过使用以下URL请求ICloud API并登录

string url = "https://setup.icloud.com/setup/ws/1/login?clientBuildNumber=1P24&clientId=" + RANDOM_GUID;

从上面的url响应获取服务器url和dsid.使用以下代码进一步请求联系人列表

var localUrl2 = "https://p66-contactsws.icloud.com/co/startup?clientBuildNumber=1P24&clientId=" + RANDOM_GUID + "&clientVersion=2.1&dsid=" + dsid + "&locale=en-EN&order=last%2Cfirst";
var webRequest2 = (HttpWebRequest)WebRequest.Create(localUrl2);
webRequest2.Method = "GET";
webRequest2.Headers.Set("Origin", "https://www.icloud.com");
// get the X-APPLE-WEBAUTH-TOKEN and X-APPLE-WEBAUTH-USER from  webResponse.Headers.SetCOOKIE
webRequest2.Headers.Set("X-APPLE-WEBAUTH-TOKEN",  XXXXXXX);
webRequest2.Headers.Set("X-APPLE-WEBAUTH-USER",  XXXXXXXX);

WebResponse webResponse2 = webRequest2.GetResponse();

仍然有例外

远程服务器返回错误:(421)错误请求.

请告诉我上面的代码有什么问题.