Code 521

Web server is down Cloudflare

The webserver behind Cloudflare (or another service that uses this resposne code) is refusing connections. This means Cloudflare tried to connect to your origin web server on port 80 or 443 but received a connection refused error. The origin web server is actively refusing the request, so this is not a network error.

sequenceDiagram participant User participant Cloudflare participant Website Note right of Website: Behind Cloudflare User ->> Cloudflare: Initial request Cloudflare ->>+ Website: Initiates TCP connection Website -->> Cloudflare: Refuses the connection Cloudflare -->> User: Returns 521 error