Firefox not opening some websites

Hi guys,

I just installed OpenSUSE Leap 42.3 on Oracle VirtualBox 5.2.8.
First thing to do was to open Firefox and try . I get “Secure Connection Failed” . Then I tried other websites (not working) ,, working). Tried also some local websites ending .bg and they all work just fine. Out of the VirtualBox I can open everything.

Did anyone faced something like that? Can this be fixed?

I’m new to Linux :slight_smile:

Thanks in advance.