Cloudflare error codes
5xx codes Cloudflare generates itself — what each one says about the origin behind it, and which are yours to fix.
Cloudflare Error 524: A Timeout Occurred, what it means and how to fix it
A 524 means Cloudflare reached your origin and waited 100 seconds for a response that never came. The network is fine; something behind that URL is too slow. How to find it.
Cloudflare Error 523: Origin Is Unreachable, what it means and how to fix it
A 523 means Cloudflare could not route to your origin server at all. Usually a DNS record pointing at the wrong IP, a dead server, or a firewall that stopped answering Cloudflare specifically.
Cloudflare Error 525: SSL Handshake Failed, causes and fixes
A 525 means Cloudflare reached your origin but could not complete a TLS handshake with it. Usually a missing or expired origin certificate, or a cipher and protocol mismatch.
Cloudflare Error 526: Invalid SSL Certificate, what it means and how to fix it
A 526 means Cloudflare completed a TLS handshake with your origin and rejected its certificate. Expired, self-signed, wrong hostname, or an incomplete chain are the four usual reasons.
Cloudflare Error 521: Web Server Is Down, what it means and how to fix it
What Cloudflare error 521 means, how a refused connection differs from 520 and 522, the four origin misconfigurations behind it, and the owner fix checklist.
Is Cloudflare down today? How to read a Cloudflare outage
When Cloudflare has an incident, thousands of sites break at once. How to confirm it's really Cloudflare, which error codes point to it, and what you can (and can't) do about it.
Cloudflare Error 520: 'Web Server Is Returning an Unknown Error'
What 520 actually says, the difference between 520 / 521 / 522 / 523 / 524, the 5 origin behaviors that cause it, and how to debug one with the cf-ray header.
Cloudflare Error 522: Connection Timed Out, what it means and how to fix it
Why 522 happens before any HTTP exchange, how it differs from 524 and 520, and the 6-step playbook for diagnosing one in under five minutes.
Cloudflare Error 1020 Access Denied: what it means and how to fix it
Error 1020 is a deliberate block by the site owner's Cloudflare firewall, not an outage. Here's how to diagnose why you're blocked and what to do next.
Cloudflare Error 1015: what "You are being rate limited" actually means
1015 is a Cloudflare-edge rate limit, not an outage. Here's why it triggers, how it differs from 1020 and 429, and what to do as a user or site owner.