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- Cloudflare errors · TroubleshootingCloudflare error 520: web server is returning an unknown errorCloudflare's catch-all error means your origin sent something empty or invalid. The usual causes and how to test your origin directly, bypassing Cloudflare.October 5, 2026 · 3 min read
- Cloudflare errors · TroubleshootingCloudflare error 521: web server is downYour origin refused Cloudflare's connection. How to tell whether the web server is stopped or a firewall is blocking Cloudflare, and how to fix both.October 5, 2026 · 3 min read
- Cloudflare errors · TroubleshootingCloudflare error 522: connection timed outCloudflare couldn't complete a connection to your server. Firewalls that drop traffic, overloaded servers and wrong origin IPs, and how to check each.October 5, 2026 · 3 min read
- Cloudflare errors · TroubleshootingCloudflare error 523: origin is unreachableCloudflare can't find a route to your server, almost always because of the IP in your DNS. How to check the record, including IPv6, and fix it.October 5, 2026 · 3 min read
- Cloudflare errors · TroubleshootingCloudflare error 524: a timeout occurredYour server took longer than Cloudflare's 100-second limit to respond. Find the slow part and move long tasks to background jobs.October 5, 2026 · 3 min read
- Cloudflare errors · TroubleshootingCloudflare error 525: SSL handshake failedCloudflare couldn't set up HTTPS with your origin. What the SSL modes mean, the common causes, and the quick fix with an Origin CA certificate.October 5, 2026 · 3 min read
- Cloudflare errors · TroubleshootingCloudflare error 526: invalid SSL certificateFull (strict) mode rejected your origin's certificate: expired, self-signed, wrong name or missing chain. How to check it and fix it properly.October 5, 2026 · 3 min read
- Browser errors · TroubleshootingERR_CONNECTION_REFUSED: what it means and how to fix itThe server is reachable but nothing accepts connections on the port. Quick checks for visitors, and the causes site owners should check first.October 5, 2026 · 4 min read
- Browser errors · TroubleshootingERR_CONNECTION_TIMED_OUT: why a site takes too long to respondNothing answered your browser at all. How to tell a firewall dropping traffic from a server that's down or a domain pointing to the wrong IP.October 5, 2026 · 4 min read
- Browser errors · TroubleshootingDNS_PROBE_FINISHED_NXDOMAIN: fix 'this site can't be reached'DNS says the domain doesn't exist. Fixes for visitors, and for owners: expired domains, missing records, moved name servers and domains on hold.October 5, 2026 · 4 min read
- Browser errors · TroubleshootingERR_TOO_MANY_REDIRECTS: find and fix a redirect loopHow to see the loop, and the usual culprits: Cloudflare Flexible SSL, layers that disagree on www or HTTPS, WordPress URLs and cookie loops.October 5, 2026 · 4 min read
- Browser errors · TroubleshootingERR_CONNECTION_RESET: what cuts the connection and how to fix itSomething hung up mid-connection. The causes on the visitor's side and the server's: crashes, firewalls, keep-alive mismatches and TLS problems.October 5, 2026 · 3 min read