523 🟧 Cloudflare

Cloudflare Error 523: Origin is unreachable

Cloudflare can’t find a network route to your origin server — the DNS record points to a wrong/unroutable IP or the origin network is down.

Seen on: Cloudflare

Meaning

Unlike 521 (origin refused) or 522 (timed out), 523 means Cloudflare couldn’t route to the IP at all: the A/AAAA record is outdated after a server move, uses a private IP, or the hosting provider has a network/BGP outage.

Common causes

  • DNS A/AAAA record points to an old or wrong IP
  • Private/reserved IP in a proxied record
  • Origin host’s network outage
  • IPv6 record without working IPv6 on the origin

⚡ Quick fix

  1. Confirm the origin IP in Cloudflare DNS matches your server
  2. Remove broken AAAA records
  3. Check the host’s status page/network

Detailed fix by platform

Shell

  1. bash
    curl -sv --resolve example.com:443:203.0.113.10 https://example.com/ -o /dev/null   # bypass Cloudflare to test the origin
dig +short AAAA example.com @1.1.1.1

How to diagnose

  1. DNS — Record IP vs server IP
  2. Origin — Reachable directly?
  3. IPv6 — AAAA working?

🔧 Still not fixed?

Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:

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