Cloudflare is actively disabling access to some pirate site URLs on its network, informing visitors that the requested pages are unavailable for legal reasons. While these types of ‘HTTP 451’ error messages are relatively rare, they are nothing more than Cloudflare complying with its legal obligations under the DMCA.
I switched to Quad9 since I like how they fought and finally won on appeal the Sony lawsuit (see https://torrentfreak.com/dns-resolver-quad9-wins-pirate-site-blocking-appeal-against-sony-231208/)