SslHandshakeFailedError is encountered in VerifyPeer mode by Self-signed certificate

// code placeholder
    QNetworkAccessManager access;
    QSslConfiguration sslConfig;
    QList<QSslCertificate> listCa;   
    QNetworkRequest request;
    QFile pem("/home/wn/cert.pem");
    QFile pem1("/home/wn/cert1.pem");
    pem.open(QIODevice::ReadOnly);
    pem1.open(QIODevice::ReadOnly);
    QByteArray arr = pem.readAll();
    QByteArray arr1 = pem1.readAll();   
    QSslCertificate cert(arr, QSsl::Pem);
    QSslCertificate cert1(arr1, QSsl::Pem);    
    listCa << cert << cert1;    
    sslConfig = QSslConfiguration::defaultConfiguration();
    sslConfig.setCaCertificates(listCa);
    sslConfig.setProtocol(QSsl::TlsV1_0OrLater);
    sslConfig.setPeerVerifyMode(QSslSocket::VerifyPeer);
    sslConfig.setPeerVerifyDepth(1);    
    request.setSslConfiguration(sslConfig);
    request.setUrl(QUrl(QString("https://192.168.20.211:6094/CasCenterApi/v3.0/authSiginbyCa")));
    QByteArray body;            
    access.post(request, body);