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Error : "Protocol \"https\" is unknown"

  • Hello i am trying to make a request to HTTPS url , i am getting following error
    Error : "Protocol \"https\" is unknown"

    below code works fine for the HTTP request but not for HTTPS

    #include <QCoreApplication>
    #include <QNetworkAccessManager>
    #include <QNetworkRequest>
    #include <QNetworkReply>
    #include <QUrl>
    #include <QUrlQuery>
    #include <QDebug>
    #include <QString>
    int main(int argc, char *argv[])
        QCoreApplication a(argc, argv);
         QString requested_url = "";
        // create custom temporary event loop on stack
        QEventLoop eventLoop;
        // "quit()" the event-loop, when the network request "finished()"
        QNetworkAccessManager mgr;
        QObject::connect(&mgr, SIGNAL(finished(QNetworkReply*)), &eventLoop, SLOT(quit()));
        // the HTTP request
        QNetworkRequest req( requested_url );
        QSslConfiguration conf = req.sslConfiguration();
        QNetworkReply *reply = mgr.get(req);
        if (reply->error() == QNetworkReply::NoError) {
    	qDebug() << (QString)reply->readAll();
        else {
    	qDebug() << "Error : " << reply->errorString();
        return a.exec();

    i am using Qt 5.9.2 on CentOS 7

  • Lifetime Qt Champion


    How did you install Qt ?
    What version of OpenSSL do you have installed ?

  • openssl : OpenSSL 1.0.2k-fips 26 Jan 2017

    offline installer for qt

  • Lifetime Qt Champion

    Do you have the same issue if you use your distribution provided Qt ?

  • @sgaist i am not sure how to check it.

  • Lifetime Qt Champion

    try to install qt and see what version it has

    yum install qt

    check whats installed

    yum list qt*

  • Lifetime Qt Champion

    Hence our suggestions: use your distribution package manager to install Qt and test that this version is working properly first.

  • hey i didn't fixed it . i downloaded Qt5.12.4 and then upgraded my openssl lib to 1.1.1b

    so i am good now
    thanks !!