无法通过XMPP连接FCM服务器

Question

我收到连接错误，因为无法连接，因为目标计算机主动拒绝它74.125.24.188:5235

代码：

xmppClient.XmppDomain = "gcm.googleapis.com";
        xmppClient.Hostname = "fcm-xmpp.googleapis.com";
        xmppClient.Port = 5235;

        xmppClient.ResolveSrvRecords = false;
        xmppClient.OldStyleSsl = true;

        xmppClient.Username = senderId;     // your sender id
        xmppClient.Password = serverKey;    // your server key

        xmppClient.AutoRoster = false;
        xmppClient.AutoPresence = false;
                 xmppClient.Open();

                   var jsonMessgae = new JObject(new
        {
            notification = new
            {
                title = "Portugal vs. Denmark",
                body = "5 to 1"
            },
            message_id = Guid.NewGuid().ToString(),
            to = testDeviceId
        });

        var msg = new Message { Id = Guid.NewGuid().ToString() };
        msg.Add(new Gcm { Value = jsonMessgae.ToString() });

        xmppClient.Send(msg);