Thanks for the answers Manny and Patrick. I followed this article to make the settings on my server: https://digitaldavo.wordpress.com/2016/01/13/using-free-letsencrypt-https-ssl-on-bitnami-lamp-on-ec2/
It’s certainly a problem with Apache as Patrick commented, but I have not figured it out yet.
I’ll try to post here the data that Patrick asked for.