Android : can't connect android device to centos vm

I'm having problems connecting to a virtual machine from an android device to test an app.

I've been reading all the posts related to this error, but still can't solve it. I don't know much about networks.

I'm getting the error "java.net.UnknownHostException: Unable to resolve host "www.votatron.local": No address associated with hostname"

I put the www.votatron.local domain in my windows host file. I can correctly access the server from my PC browsers (chrome and firefox). I do a request with HTTP REQUESTER to my PHP script and I get the right response.

The problem comes when using the android device or the android emulator. I can't seem to access the domain from the app and from the device's browser.

I have the right permissions set in my manifest (INTERNET & ACCESS_NETWORK_STATE).

I have disconnected the LAN adapter, and both, the PC and the android device, connect to the same WIFI connection.

I'm stuck with this issue for 4 days now and can't seem to solve it. As i said I don't know much about networks.

By the way, I checked my chrome(pc) settings and It seems it's not conecting through a proxy.

Thanks in advance for any help.

This is the AsyncTask I'm using to connect:

private class CheckInAsyncTask extends AsyncTask<String, Integer, Boolean> {

    @Override
    protected Boolean doInBackground(String... params) {
        boolean exito = false;
        InputStream is = null;
        int len = 1000;

        // Gets the URL from the UI's text field.
        String stringUrl = getResources().getString(R.string.url_login_php_script);
        ConnectivityManager connMgr = (ConnectivityManager)
                getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connMgr.getActiveNetworkInfo();
        if (networkInfo != null && networkInfo.isConnected()) {
            URL url;
            HttpURLConnection conn;
            try {
                //url = new URL(stringUrl);
                //url = new URL("http://172.16.100.5:9090/login_registro.php");
                //url = new URL("http://172.16.100.5/login_registro.php");
                //url = new URL("http://172.16.100.5:8080/login_registro.php");
                url = new URL("http://www.votatron.local/login_registro.php");

                String param="email=" + URLEncoder.encode(email, "UTF-8");

                conn = (HttpURLConnection) url.openConnection();
                conn.setReadTimeout(10000 /* milliseconds */);
                conn.setConnectTimeout(15000 /* milliseconds */);
                conn.setDoOutput(true);

                conn.setFixedLengthStreamingMode(param.getBytes().length);
                conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
                PrintWriter out = new PrintWriter(conn.getOutputStream());
                out.print(param);
                out.close();

                String response= "";

                Log.e("ERROR -----------> ", "HOLAAAAaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaAA");

                // LA SIGUIENTE LINEA ESTÁ DANDO ERROR
                Scanner inStream = new Scanner(conn.getInputStream(), conn.getContentEncoding());
                while(inStream.hasNextLine()) {
                    response += (inStream.nextLine());
                }

                char[] respuestaArray = response.toCharArray();
                int respuestaNum = Integer.parseInt(Character.toString(respuestaArray[respuestaArray.length-1]));

                if(respuestaNum==1){
                    //lanzo la aplicacion
                    exito = true;
                } else if (respuestaNum==0){
                    // repito el proceso
                    exito = false;
                }

            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (ProtocolException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if (is != null) {
                    try {
                        is.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }

        } else {
            Toast.makeText(getApplicationContext(), "imposible realizar la conexion con el servicio", Toast.LENGTH_LONG).show();
            exito = false;
        }
        return exito;
    }

    @Override
    protected void onProgressUpdate(Integer... values) {
        //super.onProgressUpdate(values);

    }

    @Override
    protected void onPostExecute(Boolean aBoolean) {
        //super.onPostExecute(aBoolean);
        if(aBoolean){
            // cierro esta actividad y abro la actividad principal
            Intent entrarApp = new Intent().setClass(MainActivity.this,
                    com.votatron.votatron.Principal.class);
            startActivity(entrarApp);
            finish();
        } else {
            // repito el proceso
            new CheckInAsyncTask().execute(email);
        }
    }
}