从asp.net C＃向Iphone发送推送通知

` public void pushMessage(string deviceID)
        {
            int port = 30;
            String hostname = "gateway.sandbox.push.apple.com";
            String certificatePath = HttpContext.Current.Server.MapPath("PushKey.p12");
            X509Certificate2 clientCertificate = new X509Certificate2(System.IO.File.ReadAllBytes(certificatePath), "mypassword");
            X509Certificate2Collection certificatesCollection = new X509Certificate2Collection(clientCertificate);

            TcpClient client = new TcpClient(hostname, port);
            SslStream sslStream = new SslStream(client.GetStream(), false, new RemoteCertificateValidationCallback(ValidateServerCertificate), null);

            try
            {
                sslStream.AuthenticateAsClient(hostname, certificatesCollection, SslProtocols.Ssl3, false);
                MemoryStream memoryStream = new MemoryStream();
                BinaryWriter writer = new BinaryWriter(memoryStream);
                writer.Write((byte)0);
                writer.Write((byte)0);
                writer.Write((byte)32);

                writer.Write(HexStringToByteArray(deviceID.ToUpper()));
                String payload = "{\"aps\":{\"alert\":\"" + "Hi,, This Is a Sample Push Notification For IPhone.." + "\",\"badge\":1,\"sound\":\"default\"}}";
                writer.Write((byte)0);
                writer.Write((byte)payload.Length);
                byte[] b1 = System.Text.Encoding.UTF8.GetBytes(payload);
                writer.Write(b1);
                writer.Flush();
                byte[] array = memoryStream.ToArray();
                sslStream.Write(array);
                sslStream.Flush();
                client.Close();
            }
            catch (System.Security.Authentication.AuthenticationException ex)
            {
                client.Close();
            }
            catch (Exception e)
            {
                client.Close();
            }
        }

              public static byte[] HexStringToByteArray(string hex)
        {
            return Enumerable.Range(0, hex.Length)
                             .Where(x => x % 2 == 0)
                             .Select(x => Convert.ToByte(hex.Substring(x, 2), 16))
                             .ToArray();
        }`

错误显示如下：

System.Net.Sockets.SocketException：连接尝试失败
，因为连接方在
时间段或已建立连接后没有正确响应失败，因为连接的主机有
无法响应17.110.227.100:30

System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 17.110.227.100:30

在System.Net.Sockets.TcpClient..ctor（字符串主机名，Int32端口）

at System.Net.Sockets.TcpClient..ctor(String hostname, Int32 port)