forum.pistar.uk

I keep getting an error 521 "Web server is down" when I try to access pistar.uk ; pistar.uk/fcsreflectors.php ; and pistar.uk/ysfreflectors.php on two different Windows 10 computers that are both running Firefox and Brave browsers. I can easily connect to the above websites using my Windows 8.1 laptop, so the problems is with Windows 10. I search the web and did not find out how to remove cloudflare from my machines. Any thoughts on getting rid of this annoyance? Also the error 521 page says my browser and Cloudflare are working and the pistar Host has the error.
Thanks

Thanks for the explanation and the urls. The https works fine.

According to this https://www.isitdownrightnow.com/pistar.uk.html it can't connect either. Says it's down for everyone.