HTTP 523 (Origin Is Unreachable): meaning and handling

Status / error code:		Category:

Constant name:
Source:		Operating System:
Description: HTTP 523 is a Cloudflare response indicating that no route to the origin could be established.

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HTTP_STATUS_CONNECTION_TIMED_OUT	HTTP_STATUS_TIMEOUT_OCCURED

HTTP_STATUS_ORIGIN_IS_UNREACHABLE

Cloudflare documents this as an origin reachability problem, commonly caused by incorrect DNS origin addresses or routing between Cloudflare and the server. It is not an HTTP application error generated by the origin.

Confirm A and AAAA records, the origin public address, and network routes. In cloud networks, inspect route tables that could incorrectly capture Cloudflare address ranges.

A 523 points to the network path from Cloudflare toward the configured origin. Verify the origin address in DNS, routing to that address, and whether the host is reachable from the Internet or expected Cloudflare networks. Application-level changes cannot repair an incorrect origin IP or missing route.

Cloudflare: Error 523

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