QSslSocke fails to set Server Name Indication on Android

Hi,
when trying to connect to https://helloworld.letsencrypt.org I get a QSslError due server hostname mismatch that's because the SNI was not set, the warning is issued:
"could not set SSL_CTRL_SET_TLSEXT_HOSTNAME, Server Name Indication disabled"
On my old phone with Android 4.4 it seems setting SNI works fine, but on Android 5 and 6, it fails.

I find this rather critical as ignoring QSslError::HostNameMismatch just make the secure process useless.