Getting Error Code 521 on My Site – How Do I Fix It? or What Causes Error Code 521 and How Can I Reso

Pro tip: Cloudflare’s "Pause" feature is your friend. Hit pause for 5 mins to rule out if it’s them or your server.

If the error persists, it’s 100% your host’s fault. Time to spam their support chat.

Also, check your server’s error logs—/var/log/nginx/error.log or similar. Might reveal the real culprit.