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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.
Operational meaning of HTTP 523 for HTTP_STATUS_ORIGIN_IS_UNREACHABLE
HTTP 523 (HTTP_STATUS_ORIGIN_IS_UNREACHABLE) is a server-error response. AllStat records its meaning as “523 Origin Is Unreachable”. For HTTP_STATUS_ORIGIN_IS_UNREACHABLE, interpret it with the request method, selected representation, response headers, and the specification or product that defines the code; the number alone does not prove that application work completed.
Client and server handling for HTTP_STATUS_ORIGIN_IS_UNREACHABLE
- Correlate HTTP_STATUS_ORIGIN_IS_UNREACHABLE with origin, gateway, load-balancer, and dependency logs to locate which hop generated it.
- For HTTP_STATUS_ORIGIN_IS_UNREACHABLE, record request and trace identifiers, upstream timing, retry count, and the health of the selected backend.
- For HTTP_STATUS_ORIGIN_IS_UNREACHABLE, use bounded retries with backoff only for idempotent work and only when the service policy permits them.
For telemetry, record HTTP 523, method, authority, route template rather than secrets, response headers relevant to caching or retry, latency, upstream identity, and whether the response originated at the application or an intermediary.
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