HTTP 523 — Origin Is Unreachable
HTTP 523
Origin Is Unreachable
Cloudflare cannot route to the origin server at all — as far as the network is concerned, it does not exist.
What 523 actually means
A Cloudflare code, not standard HTTP. It sits one layer below 521 and 522: the problem is not that the server refused or timed out, but that Cloudflare could not reach the address at all. The usual explanation is a DNS record pointing at an IP that is no longer yours, or that never was — after a server migration where the record was not updated, for example.
Common causes
- The origin IP address in DNS is wrong, stale, or belongs to a decommissioned server
- A server migration where the DNS record was not updated
- BGP or routing problems between Cloudflare and the origin network
- The origin host powered off or terminated
- A CNAME chain resolving to something unroutable
If you're just trying to view the page
- Nothing you can do — the site's origin address is unreachable from Cloudflare
- Try again later, and report it to the site owner with the Ray ID
If it's your site
- Check that the A/AAAA record in Cloudflare's DNS matches the current origin IP address
- Confirm the origin host is running and has the IP you think it has
- Test routing to the origin from an external network with `mtr` or `traceroute`
- If you use a CNAME to another provider, verify that chain resolves to something routable
Reference
- Status code
- 523
- Reason phrase
- Origin Is Unreachable
- Category
- 5xx — Server Error
- Cacheable by default
- No
Common questions
- What does HTTP 523 mean?
- Cloudflare cannot route to the origin server at all — as far as the network is concerned, it does not exist. A Cloudflare code, not standard HTTP. It sits one layer below 521 and 522: the problem is not that the server refused or timed out, but that Cloudflare could not reach the address at all.
- How do I fix a 523 error?
- Nothing you can do — the site's origin address is unreachable from Cloudflare
- Is 523 a client error or a server error?
- 523 is in the 5xx range, which means server error. The request was acceptable but the server could not fulfil it, so retrying later can succeed.
Related pages
- 500 Internal Server Error Something went wrong on the server and it has no more specific code to describe
- 502 Bad Gateway A proxy or gateway reached the server behind it and got back a broken response,
- 503 Service Unavailable The server is temporarily unable to handle the request, usually because it is ov
- 504 Gateway Timeout A proxy or gateway waited for the server behind it and gave up before an answer
- 524 A Timeout Occurred Cloudflare connected to the origin successfully but the origin did not finish re
- 521 Web Server Is Down Cloudflare could not connect to the origin server because it refused the connect
- 522 Connection Timed Out Cloudflare tried to open a connection to the origin server and never got a reply
- 520 Web Server Returned an Unknown Error Cloudflare reached the origin server but got back a response it could not make s
- 525 SSL Handshake Failed The TLS handshake between Cloudflare and the origin server failed.
- 526 Invalid SSL Certificate The origin server presented a TLS certificate that Cloudflare could not validate
- 530 Origin DNS Error A Cloudflare error shown alongside a 1xxx error code that carries the real expla
- 501 Not Implemented The server does not support the functionality needed to fulfil the request, usua