Cloudflare, reporting that the origin refused the connection.
Cloudflare error 521 — Web server is down
Cloudflare could not open a connection to the origin at all. Note the difference from 522: this is a refusal, arriving immediately, rather than a timeout after waiting — which usually means nothing is listening.
A proxy does not fix this. The site is down for everyone. There is nothing to route around.
Why it happens
The origin process is not running.
The origin firewall is dropping Cloudflare's IP ranges.
The origin listens on a port Cloudflare is not configured to reach.
How to fix it
- Wait and retry — this is entirely on the site's side.
- Confirm it is not just you by checking the domain from another network.
FAQ
What does 521 mean?›
Cloudflare could not open a connection to the origin at all. Note the difference from 522: this is a refusal, arriving immediately, rather than a timeout after waiting — which usually means nothing is listening. Cloudflare, reporting that the origin refused the connection.
Why am I getting 521?›
The origin process is not running. The origin firewall is dropping Cloudflare's IP ranges. The origin listens on a port Cloudflare is not configured to reach.
How do I fix 521?›
Wait and retry — this is entirely on the site's side. Confirm it is not just you by checking the domain from another network.
Will a proxy fix 521?›
The site is down for everyone. There is nothing to route around.