ssl websocketserver stops accepting new connections

[...]
void QSslServer::incomingConnection(qintptr socket)
{
    QSslSocket *pSslSocket = new QSslSocket();

    if (Q_LIKELY(pSslSocket)) {
        pSslSocket->setSslConfiguration(m_sslConfiguration);

        if (Q_LIKELY(pSslSocket->setSocketDescriptor(socket))) {
            connect(pSslSocket, &QSslSocket::peerVerifyError, this, &QSslServer::peerVerifyError);

            typedef void (QSslSocket::* sslErrorsSignal)(const QList<QSslError> &);
            connect(pSslSocket, static_cast<sslErrorsSignal>(&QSslSocket::sslErrors),
                    this, &QSslServer::sslErrors);
            connect(pSslSocket, &QSslSocket::encrypted, this, &QSslServer::newEncryptedConnection);
            connect(pSslSocket, &QSslSocket::preSharedKeyAuthenticationRequired, this, &QSslServer::preSharedKeyAuthenticationRequired);

            addPendingConnection(pSslSocket);

            pSslSocket->startServerEncryption();
        } else {
           delete pSslSocket;
        }
    }
}
[...]

// Tested with SslEchClient changed
// void SslEchoClient::onTextMessageReceived(QString message)
// {
//     qDebug() << "Message received:" << message;
//     //qApp->quit(); -- disabled
// }

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    new SslEchoClient(QUrl(QStringLiteral("wss://localhost:1234")));

    for (int i = 0; i < 40; i++)
        new SslEchoClient(QUrl(QStringLiteral("ws://localhost:1234")));

    QTimer::singleShot(2500, [&] {
        a.quit();
    });

    return a.exec();
}