Android не подключается к СУБД MySQL через PHP

Выполняю работу по примеру, но почему то приложение не добавляет запись в БД, хотя если в php изменить переменные на текст, то запись при выполнении php-файла добавится. В Android Studio в manifest internet добавил

public void userReg(View view) {
    String name="Данил";
    String messages="Тестовое отправление";
    String order_id="1";
    String fromFirebaseId="f9AopqZ4mKI:APA91bFayy2W8mXf-TqIzdg4IJ4xMGMYW2r_Ppgkd8W7nKQ5MxgKDqkkaS-pHfxHXmH3v-pAXtiZSNSGHb2e2zuznlPyn14so8tcqvkg6Dl5WXm_aHe0qGVGx7Qt3-rj1JG15ji0B-rn";
    AddMessages addMessages=new AddMessages(this);
    addMessages.execute(name, messages, order_id, fromFirebaseId);
}
class AddMessages extends AsyncTask<String, Void, String> {
    AlertDialog alertDialog;
    Context ctx;
    AddMessages(Context ctx){
        this.ctx=ctx;
    };
    @Override
    protected void onPreExecute() {
       alertDialog=new AlertDialog.Builder(ctx).create();
        alertDialog.setTitle("Добавление сообщения статус");
    }
    protected String doInBackground(String... args) {
        String addMessages_url = "http://test2.ru/register.php";
        String name=args[0];
        String messages=args[1];
        String order_id=args[2];
        String fromFirebaseId=args[3];
        URL url = null;
        try {
            url = new URL(addMessages_url);
            HttpURLConnection httpURLConnection=(HttpURLConnection)url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoInput(true);
            httpURLConnection.setDoOutput(true);
            OutputStream OS = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(OS,"UTF-8"));
        String data=URLEncoder.encode("name","UTF-8")+"="+URLEncoder.encode(name,"UTF-8")+"&"+
                URLEncoder.encode("messages","UTF-8")+"="+URLEncoder.encode(messages,"UTF-8")+"&"+
                URLEncoder.encode("order_id","UTF-8")+"="+URLEncoder.encode(order_id,"UTF-8")+"&"+
                URLEncoder.encode("fromFirebaseId","UTF-8")+"="+URLEncoder.encode(fromFirebaseId,"UTF-8");
            bufferedWriter.write(data);
            bufferedWriter.flush();
            bufferedWriter.close();
            OS.close();
            InputStream IS = httpURLConnection.getInputStream();
            BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(IS,"iso-8859"));
            String result="";
            String line="";
            while((line=bufferedReader.readLine())!=null){
                result+=line;
            }
            bufferedReader.close();
            IS.close();
            httpURLConnection.disconnect();
            return result;
        } catch (MalformedURLException e1) {
            e1.printStackTrace();
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        return null;
    }
    protected void onPostExecute(String result) {
        alertDialog.setMessage(result);
        alertDialog.show();
    }
}

require "init.php";
$name=$_POST["name"];
$messages=$_POST["messages"];
$order_id=$_POST["order_id"];
$fromFirebaseId=$_POST["fromFirebaseId"];
$sql_query="insert into messages values 
('$name','$messages','$order_id','$fromFirebaseId')";
if(mysqli_query($con, $sql_query)){
echo "Data Insertion Success";
}
else{
echo "Data insertion error";
}