Page not working

Hi,
I have a serious problem with this website https://www.darsipace.it

In particular ALL THE PAGE are not working. If I want to go in the page “Identita”

https://www.darsipace.it/identita , I have the blank page. Why?

But if I enter in the preview mode, I see the complete page.

How it is possible?

It’s a theme’s problem?

Thank you