Please double check configure website -> edit directives that DocumentRoot points for the right directory.
Also check under Webmin -> Servers -> Apache that all non SSL host have set Address to ANY and SSL have IP
Thank you for your answers. As a freelancer you can imagine (or live it) that I have 10,000 tasks to manage. So I have not had time to take into account your answers.
I will test these solutions in a few days and as soon as I have something new, I will follow it here.