QNetworkRequest: setting SSL configuration makes request fail

#include <QtCore>
#include <QtNetwork>

class Test : public QObject {

    Q_OBJECT

public:
    Test() : QObject() {
        QNetworkRequest request(QUrl("https://www.gmail.com"));

        // both lines below fail:
        QSslConfiguration conf = QSslConfiguration::defaultConfiguration();
        //QSslConfiguration conf = request.sslConfiguration();

        conf.setProtocol(QSsl::TlsV1_0);
        request.setSslConfiguration(conf);

        manager.get(request);
        connect(&manager, SIGNAL(finished(QNetworkReply*)), this, SLOT(mySlot(QNetworkReply*)));
    }
    
    QNetworkAccessManager manager;

public slots:
    void mySlot(QNetworkReply*);
};

void Test::mySlot(QNetworkReply *reply) {
    qDebug() << "mySlot called" << reply->errorString() << reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
    QCoreApplication::instance()->quit();
}

int main(int argc, char **argv) {

    QCoreApplication app(argc, argv);
    Test test;
    return app.exec();
}

#include "main.moc"