What Cloudflare 523 means
Cloudflare couldn’t reach the origin at the network level, typically because the DNS record points to the wrong or a private IP address, or the origin’s network has routing problems.
523 isn’t defined in any HTTP standard. It is specific to Cloudflare, so other servers and proxies won’t use it.
How to fix error 523
- Verify the A/AAAA records in Cloudflare DNS point to the server’s current public IP.
Retrying
Yes, usually. It is often temporary, so retry with exponential backoff and give up after a few attempts.
Example response
HTTP/1.1 523 Origin Is Unreachable
Date: Wed, 21 Oct 2026 10:30:00 GMT
Server: cloudflare
CF-RAY: 8c2f6a1e3b9d4e21-FRA
Content-Type: text/html; charset=UTF-8Related status codes
- 522 Connection Timed Out : The TCP connection to the origin server timed out.
- 521 Web Server Is Down : The origin server refused the connection.
- 502 Bad Gateway : A proxy or gateway got an invalid response from the upstream server.
Other 5xx status codes
500 Internal Server Error · 501 Not Implemented · 502 Bad Gateway · 503 Service Unavailable · 504 Gateway Timeout · 505 HTTP Version Not Supported · 507 Insufficient Storage · 508 Loop Detected · 511 Network Authentication Required · 520 Web Server Returned an Unknown Error · 521 Web Server Is Down · 522 Connection Timed Out · 524 A Timeout Occurred · 525 SSL Handshake Failed · 526 Invalid SSL Certificate
See the full list of HTTP status codes.
Sources
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Frequently asked questions
What does Cloudflare 523 Origin Is Unreachable mean?
Cloudflare 523 Origin Is Unreachable means Cloudflare can’t route to the origin server. Cloudflare couldn’t reach the origin at the network level, typically because the DNS record points to the wrong or a private IP address, or the origin’s network has routing problems.
How do I fix Cloudflare 523?
Verify the A/AAAA records in Cloudflare DNS point to the server’s current public IP.