HTTP Errors Glossary

HTTP 429 Too Many Requests is the status code a server returns when a client has sent more requests in a given window than the server's rate limit allows.

HTTP 499 Client Closed Request is a non-standard status code, logged by Nginx (and CDNs like Cloudflare) when the client closes the connection before the server finishes sending a .

HTTP 403 Forbidden means the server understood the request but refuses to fulfill it.

HTTP 503 Service Unavailable means the server is temporarily unable to handle the request — usually because it's overloaded, undergoing maintenance, or actively rejecting traffic a.

HTTP 200 OK is the standard success status code: the server received the request, processed it, and returned the expected response body.

Cloudflare error 1015 "You are being rate limited" is shown when a visitor has exceeded a rate-limiting rule configured by the site owner inside Cloudflare.

HTTP 402 Payment Required indicates the server is refusing the request until payment, billing, or quota issues are resolved.

HTTP 404 Not Found means the server understood the request but has no resource at that URL.

HTTP 520 is a non-standard Cloudflare status code meaning the origin server returned a response Cloudflare cannot interpret.

HTTP 401 Unauthorized means the request lacks valid authentication credentials.

HTTP 405 Method Not Allowed means the endpoint doesn't accept the HTTP method you used.

HTTP 406 Not Acceptable means the server can't return content matching your Accept headers.

HTTP 409 Conflict means the request conflicts with the current state of the resource.

HTTP 422 Unprocessable Entity means the request was well-formed but failed validation.

HTTP 451 Unavailable For Legal Reasons means the resource is blocked for legal or geo reasons.

HTTP 502 Bad Gateway means a gateway or proxy got an invalid response from the upstream server.

HTTP 521 Web Server Is Down (Cloudflare) means Cloudflare couldn't open a connection to the origin server.