Impossible to modify the page selected as “posts page”

Hi all,

I’m experiencing an issue with my fresh WP installation that doesn’t seems caused by any previous action or change by me.

Basically, the page selected in settings menu as “posts page” can’t be modified anymore. Standard visual editor disappeared as well as “models” under “attributes” section.

As you can see in the “Attività” page on my site, now it’s applied only the standard layout with no way to edit it.

I tried to remake the “posts page”, reinstall wp, clear the cache, change theme, disable all plugins, but nothing worked out. The problem persists only on the page selected as “posts page”.

Can someone help me out?

The page I need help with: [log in to see the link]