HttpHostConnection ; Connection refused

I am making an app using GCM.

When button clicked, method 'sendRegistrationIdToBackend' works.

but my log cat stops printing at CODE : httpclient.execute(httppost);

please help me . below is my code of method sendRegistrationIdBackend' & LocalWebServer Code

   private void sendRegistrationIdToBackend() {
    Log.v("11111","11111");

    //HttpClient httpclient = new DefaultHttpClient();
    DefaultHttpClient httpclient = new DefaultHttpClient();
    Log.v("11111","22222");

    //HttpPost httppost = new HttpPost(Constant.IP_MAC+":52273/push");
    HttpPost httppost = new HttpPost("http://223.62.173.221:52273/push");
    Log.v("11111","3333");

    try {  
        // Add your data
        Log.v("11111","44444");

        httpclient.execute(httppost);

        Log.v("11111","5555");


    } catch (ClientProtocolException e) {
        Log.v("11111","6666");

        // TODO Auto-generated catch block
    } catch (IOException e) {
        // TODO Auto-generated catch block
        Log.v("11111",Log.getStackTraceString(e));
    }
     }

a few seconds later, there is an exception : HTTP HOST CONNECTION ; CONNECTION REFUSED...

var http = require('http');
var express = require('express');

var app = express();


app.use(express.static('public'));


app.use(app.router);
app.use(express.bodyParser());


var gcm = require('node-gcm');

var message = new gcm.Message();

var message = new gcm.Message({
    collapseKey: 'demo',
    delayWhileIdle: true,
    timeToLive: 3,
    data: {
        key1: '안녕하세요.',
        key2: 'saltfactory push demo'
        }
    });

var server_access_key = '~';
var sender = new gcm.Sender(server_access_key);
var registrationIds = [];

var registration_id = '~-~-~-~-~-~';
registrationIds.push(registration_id);

app.post('/push',function(request,response){
        response.send("test_out");
        console.log("test_console");
sender.send(message, registrationIds, 4, function (err, result) 
    {
        console.log(result);
        response.send("text_in");
    });
});



sender.send(message, registrationIds, 4, function (err, result) {
     console.log(result);
});
http.createServer(app).listen(52273,function(){
    console.log('Server Running http://127.0.0.1:52273');
});

Can you help me?