Hi, so here are the Community Tips that are available by searching in the Community…
I see you put 521 in the title, but the image shows 522, so I’ll put both. Follow the second one first, I would suggest.
A 521 error happens when Cloudflare is unable to make a TCP connection to your origin server. Review the suggestions in this Community Tip for Quick Fix Ideas.
A 522 error typically happens when Cloudflare requests to the origin (your webserver) get blocked. Review the suggestions in this Community Tip for troubleshooting ideas.