asp.net – Android C2DM获取(401)未经授权

当我向C2DM发出http post请求以便手机收到消息时,我一直收到401 Unauthorized.以下是我在.NET中发出请求的方式：

WebRequest myRequest = WebRequest.Create("https://android.apis.google.com/c2dm/send");
    myRequest.ContentType = "application/x-www-form-urlencoded";
    myRequest.Method = "POST";
    myRequest.Headers.Add("Authorization","GoogleLogin auth=" + authId);
    // buiold the post string
    StringBuilder myPost = new StringBuilder();
    myPost.AppendFormat("registration_id={0}",regId);
    myPost.AppendFormat("&data.payload={0}",msg);
    myPost.AppendFormat("&collapse_key={0}",colKey);

    // write the post-string as a byte array
    byte[] myData = ASCIIEncoding.ASCII.GetBytes(myPost.ToString());
    myRequest.ContentLength = myData.Length;
    Stream myStream = myRequest.GetRequestStream();
    myStream.Write(myData,myData.Length);
    myStream.Close();
    // Do the actual request and read the response stream
    WebResponse myResponse = myRequest.GetResponse();
    Stream myResponseStream = myResponse.GetResponseStream();
    StreamReader myResponseReader = new StreamReader(myResponseStream);
    string strResponse = myResponseReader.ReadToEnd();
    myResponseReader.Close();
    myResponseStream.Close();

任何帮助将非常感激.