Setup proxy of QWebEnginePage

[tham]

I want to access the web page by free proxy I search by google, but the connection always fail

    QStringList const proxy_host{"https://www.kproxy.com/", "https://hide.me/en/proxy",
                                 "https://whoer.net/webproxy"};
    QNetworkProxy proxy;
    proxy.setType(QNetworkProxy::HttpProxy);
    proxy.setHostName(proxy_host[0]);
    proxy.setPort(8080);
    QNetworkProxy::setApplicationProxy(proxy);

All of the proxy do not work as expected, I cannot connect to https://www.bing.com/images/search?q=smoke.

Error messages:
"There is something wrong with the proxy server, or the address is incorrect"