QWebEngine self signed certificates issue

Hi,

I'm having some issue loading a internally hosted webpage in QWebEngine.
When loading the page I get the following error:

This site can’t be reached

The webpage at https://ourinternalwebsiteurl might be temporarily down or it may have moved permanently to a new web 
address.

ERR_CERT_COMMON_NAME_INVALID

The Qt Documentation says this about cert. management with QWebEngine:

Managing Certificates
Qt WebEngine uses its own network stack, and therefore QSslConfiguration
 is not used to open SSL connections. Instead, Qt WebEngine uses the 
root CA certificates from the operating system to validate the peer's 
certificate.

In our case the certificate is properly added to the OS's "Trusted Root Certification Authorities", the proof being that "Internet Explorer" which also uses the Operating System certs to validate works without any issue.

I can't test with Qt5.12.1 as QWebEngine seems to require Visual Studio 2017 to work and I only have VS2015 available.

What am I missing here ? Is this a bug in PySide2 ?
Thanks.