Cloudflare

Cloudflare Status Codes

Showing 8 status codes

Cloudflare-specific HTTP status codes (520-527) are proprietary responses used by Cloudflare's CDN and security services to indicate problems communicating with origin servers. These codes help distinguish between issues in Cloudflare's infrastructure and problems with the origin server.

The most frequently encountered Cloudflare codes are 520 Web Server Returned an Unknown Error (origin returned an empty or malformed response), 521 Web Server Is Down (origin refused the connection), 522 Connection Timed Out (TCP connection to origin timed out), and 524 A Timeout Occurred (origin didn't return a timely HTTP response).

When troubleshooting Cloudflare errors, check the origin server's health, firewall settings, and Cloudflare IP allowlisting. Many Cloudflare errors indicate the origin server needs attention, not Cloudflare itself.

🤷520cloudflareWeb Server Returns Unknown ErrorThe server just said something completely incomprehensible! Cloudflare asked your origin server a question and got back gibberish. It's like asking for directions and getting a reply in ancient hieroglyphics.
🚫521cloudflareWeb Server Is DownNobody's home! Cloudflare knocked on your server's door but it's locked up tight. Either the server shut down, went on vacation, or is hiding behind the curtains refusing to answer.
⏱️522cloudflareConnection Timed OutYour server is playing the silent game! Cloudflare connected successfully but your origin just... sits there. It's like calling someone who picks up the phone then says absolutely nothing.
🗺️523cloudflareOrigin Is UnreachableYour server fell off the internet! Cloudflare can't even find your origin server on the network. It's like having a delivery address that doesn't exist - the package can't even start the journey.
🕐524cloudflareA Timeout OccurredStill waiting... and waiting... and waiting! Your origin server accepted the call but then forgot to speak. Cloudflare gave up after waiting politely for way too long.
🔐525cloudflareSSL Handshake FailedSecret handshake failed! Cloudflare and your origin server tried to do the security handshake but couldn't agree on how to do it. It's like two spies who forgot the password.
📜526cloudflareInvalid SSL CertificateYour credentials are bogus! Cloudflare checked your origin's SSL certificate and it's either fake, expired, or signed by someone sketchy. No secure connection for you!
🚂527cloudflareRailgun ErrorThe express train broke down! Cloudflare tried to use the super-fast Railgun connection to your origin but the rail line is having issues. Time to call maintenance!

Cloudflare Status Codes FAQ

What causes Cloudflare Error 522?

Cloudflare Error 522 indicates a TCP connection timeout between Cloudflare and your origin server. Common causes include server overload, firewall blocking Cloudflare IPs, incorrect DNS settings, or the origin server being down. Check your server's availability and ensure Cloudflare IPs are allowlisted.

What does Cloudflare Error 520 mean?

Cloudflare Error 520 indicates the origin server returned an empty, unknown, or unexpected response. This often happens when the origin crashes, returns malformed headers, or the response exceeds size limits. Check your origin server logs and application errors.

How do I fix Cloudflare 521 Web Server Is Down?

Cloudflare 521 means the origin server refused the connection. Verify your origin server is running, check that it's listening on the correct ports (80/443), ensure Cloudflare IPs aren't blocked by your firewall, and confirm your Cloudflare DNS settings point to the correct origin IP.