envoyer des notifications push à l'Iphone à partir de asp.net C#

` 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();
}`

l'erreur montre ci-dessous :

Système.Net.Les Sockets.Exception socketexception: Une tentative de connexion a échoué
car le parti connecté n'a pas répondu convenablement après une période de
temps, ou une connexion établie a échoué car l'hôte connecté a
n'a pas pu répondre 17.110.227.100:30

au Système.Net.Les Sockets.TcpClient..ctor(String hostname, Int32 port)