QNetworkReply::RemoteHostClosedError - qt

Question

I was learning the Github API and wanted to create an Issue on github by Qt.
But, when I submit my Issue, the "Debug Console" said
QNetworkReply::RemoteHostClosedError
(I catched error).
I don't know why, please help me!
Code on Github:
void MainWindow::on_pushButton_2_clicked()
{
QString id = ui->ID_Send->text();
QJsonObject JJ;
QJsonDocument jd;
JJ["title"] = ui->Title->text();
JJ["body"] = ui->Comment->toPlainText();
QHttpMultiPart *part = new QHttpMultiPart(QHttpMultiPart::FormDataType);
QHttpPart info;
info.setHeader(QNetworkRequest::ContentTypeHeader, QVariant("text/json"));
jd.setObject(JJ);
info.setBody(jd.toJson());
part->append(info);
QNetworkRequest request;
qDebug()<<"https://api.github.com/repos/MoyuSteve/Comment/issues?client_id="+
client_id+"&client_secret="+client_secret;
request.setUrl(QUrl("https://api.github.com/repos/MoyuSteve/Comment/issues?client_id="+
client_id+"&client_secret="+client_secret));
QNetworkReply* reply = manager->post(request,part);
QObject::connect(reply, &QNetworkReply::finished, [reply, this] () {
if (reply->error() == QNetworkReply::NoError) {
ui->status->setText("ok");
} else {
ui->status->setText("failed");
qDebug()<<reply->error();
}
reply->deleteLater();
});
}

Answer 1

You can take example in this answer or here.
Compared to your code, it sets the header to "application/json".
And it uses a QNetworkAccessManager to send network requests and receive replies.
QUrl url("https://api.github.com/repos/" + owner +"/" + project + "/tags");
qInfo() << url.toString();
QNetworkRequest request(url);
request.setHeader(QNetworkRequest::ContentTypeHeader, "application/json");
QNetworkAccessManager nam;
QNetworkReply * reply = nam.get(request);