Scroll offset not working

Hi,
I have a fixed header and I’m trying to adjust the offset position but it seems this feature is not working on my website: https://techpeople.it/miglior-microsoft-surface-pro/

There’s something I have to check to enable this feature? As you can see the anchor links are overlapped by the menu header both on desktop and mobile devices.

Thanks for helping!
Angelo

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