I don't know what you mean with:
Do I have a .well-known directory?
How do I make sure that it is accessible? I checked and, right now, only the main page is accessible, I can access none of the other pages; I get an error: The requested URL /preguntas.php was not found on this server (to name one of the pages, for example).
I logged into Plesk and there's a .well-known directory under public_html, permissions for group and others are read and execute, is it accessible as is, or should it have also write access for group and/or others? Would that be secure?
Also, permissions for the files of my pages (preguntas.php, quienes_somos.php, contacto.php and productos.php), are all the same: Owner: rw-, Group and Others: r--. Same for index.php, but only it is accessible. My whole site is gone now!
I only get the Web Server's Default Page, and Plesk states that: "You see this page because there is no Web site at this address." Well, there was!