Request POST Using QNetworkReply timeout

Question

I'm using QtCreator based on version 4.8 to develop an application for a device that uses linux with operating system.

I'm trying to make a POST order in QT I am using the following libraries

#include <QNetworkAccessManager>
#include <QNetworkRequest>
#include <QNetworkReply>

I have the following code snippets

{
    QString msg;
    QString url = "myURL";
    QNetworkRequest request = QNetworkRequest(QUrl(url));
    request.setHeader(QNetworkRequest::ContentTypeHeader, QVariant("application/json; charset=UTF-8"));

    QString message = QString("{\"message\" : %1}").arg("\"hello\"");

    QByteArray AliveJson = message.toLatin1();

    reply = manager->post(request, AliveJson);
    
    connect(manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(finished(QNetworkReply*)));
}

void page100::finished(QNetworkReply *r)
{
    qDebug()<<"METOD FINISHED CALLED!";
    QString msg;
    qDebug()<< r;
    qDebug()<< "-----------------------------";
    qDebug()<< reply;
    if (r == reply) {
        int status = r->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
        if (r->error() == QNetworkReply::NoError && status >= 200 && status < 300) {
            msg = QString("successfull reply (%1)").arg(status);//200
            qDebug()<<reply->readAll();
        } else {
            msg = QString("failure reply (%1), %2").arg(status).arg(r->errorString());
            qDebug()<<msg;
        }
        reply = NULL;
    } else {
        msg = QString("unknown reply, url=%1").arg(r->url().toString());
       qDebug()<<msg;
    }
    r->deleteLater();
    ui->plainTextEdit->setPlainText(ui->plainTextEdit->toPlainText() + msg);
    qDebug()<<msg;
}

I always get the following error

failure reply(0), socket operation timed out

I tried to create a new url to communicate but I keep getting the same error.

device is properly connected to the internet. I have already done ping procedures and the device communicates correctly