My guess is .. your internet provider is blocking that website as a suspicious site.
(which is none of their dam business)

When you see things like that click your uBlock and then click the little eye dropper.
The page will turn orange and block your internet providers blocker. LOL

At least it does when my stupid Spectrum blocks something they don't like.
Usually because the website is http and not https.
The idiots often block some of my old web pages.