Unsolved QApplication::exec: Must be called from the main thread

[hndery]

Hi again,
i've got a question again again,,i know this is really unnecessary question.
But u know.. "question = new question" :D
i've got one lineEdit for entry url,one button for load and one webView for showing youtube videos.for videos i used youtube embed videos url. for simple explane;

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QNetworkProxyFactory>
#include <QRegExp>


MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) {
	ui->setupUi(this);
	QNetworkProxyFactory::setUseSystemConfiguration (true);
	QWebSettings::globalSettings()->setAttribute(QWebSettings::PluginsEnabled, true);
	QWebSettings::globalSettings()->setAttribute(QWebSettings::AutoLoadImages, true);
}


MainWindow::~MainWindow() {
	delete ui;
}


void MainWindow::on_loadButton_clicked() {
	QRegExp exp("youtu(?:\\.be|be\\.com)/(?:.*v(?:/|=)|(?:.*/)?)([a-zA-Z0-9-_]+)");
	exp.indexIn(ui->textURL->text());
	if( exp.capturedTexts().length() >= 2 ) {
		QString video_url = "http://www.youtube.com/embed/";
		video_url += exp.capturedTexts().at(1);
		ui->webView->load( QUrl( video_url ));
	}
}
//https://www.youtube.com/watch?v=LsKFsF2zpFM
//https://youtu.be/LsKFsF2zpFM

trying to "https://www.youtube.com/watch?v=EIoBvWTzkTY&t=4s"
and this work very well

except live broadcast videos

when i try to open live broadcast ;
"https://www.youtube.com/watch?v=21X5lGlDOfg" <<live link

Application Output:
QApplication::exec: Must be called from the main thread

why and how i fix that

thanks your patience for my silly questions.have good day for all.

[Christian Ehrlicher]

You showed us a lot of stuff but nothing where you instantiate your QApplication which is what the error is about.

[kshegunov]

To add to @Christian-Ehrlicher, setting QT_FATAL_WARNINGS in the environment can also give you stack trace about the warning, which'd be immensely helpful to track down where and why this happens.