HTTP 523 in Cloudflare

Cloudflare can't route to the origin — DNS mismatch or origin IP unreachable.

Why Cloudflare returns 523

Cloudflare can't route to the origin — DNS mismatch or origin IP unreachable.

How to fix it

Verify the A/AAAA record for the origin and that the IP is publicly routable.

Where this surfaces in Cloudflare

The Cloudflare edge before your origin ever sees the request. Look at the Ray ID in the response.

Cloudflare — CDN, WAF, and edge network in front of your origin.

What HTTP 523 means generally

Cloudflare could not reach the origin server, likely due to DNS issues.

HTTP 523 is a Cloudflare-specific error meaning Cloudflare cannot resolve the origin server's DNS or route to its IP address.

Other common causes of 523

SEO impact

Complete site outage through Cloudflare. Will be treated as downtime by search engines.

How to catch it next time

LemWatch monitors DNS resolution as part of its checks and can detect when origin IP changes cause reachability issues.