Clean Firefox (no addons) from Italy, no paywall or ad-wall.

I have the no-tracking enabled in the FF preferences and I'm on Ubuntu MATE 16.04 LTS.

Workaround: open the link in a private window.

no paywall for me - is it geotargetted?

I see an anti-ad wall, when I whitelist the page or turn off the adblocker it works

What's wrong with that? As far as I know the point of open science is that research publications should be open not everything else, too. For non-science publications like newspapers I actually prefer payed access over ad-supported access.