Problem with Root CA Pinning on IOS

Hi, 

I try to do Root CA certificatres pinning and it's not working on IOS. I have app that works both on Windows and IOS. I create CustomNetworkAccessManager by inherit from QNetworkAccessManager. I create own configuration with own RootCA like that: 

QSslConfiguration sslConfig = QSslConfiguration::defaultConfiguration();
QList<QSslCertificate> caCerts;
caCerts.append(caCert1);
caCerts.append(caCert2);
sslConfig.setCaCertificates(caCerts); 
QSslConfiguration::setDefaultConfiguration(sslConfig)

I also connect sslErrors signal with my own sslErrorHandler

connect(this, &QNetworkAccessManager::sslErrors, this, &CustomNetworkAccessManager::handleSslErrors);

It works as expected on Windows but on IOS it seems like all this is ignored. There is not a signle call to handleSslErrors. 
 
Does something need to be setup on IOS or it's Qt issue?