#include <QSslSocket>
#include <QDebug>
#include <QUrl>
int main(){
    QSslSocket::setActiveBackend("schannel");
    qDebug() << "Current TLS backend:" << QSslSocket::activeBackend();
    qDebug() << "Available TLS backends:" << QSslSocket::availableBackends();
    QUrl url("https://www.久盛电缆.com");
    auto test = [&](const QString &host) {
        QSslSocket socket;
        socket.connectToHostEncrypted(host, 443);
        if (!socket.waitForEncrypted()) {
            qDebug() << host << socket.errorString();
        } else {
            qDebug() << host << "Handshake succeeded";
        }
    };
    test(url.host());
    test(url.host(QUrl::EncodeUnicode));
}

Current TLS backend: "schannel"
Available TLS backends: QList("cert-only", "openssl", "schannel")
"www.久盛电缆.com" "Handshake failed: Internal error"
"www.xn--3iq226gfdb94q.com" Handshake succeeded