Status class · Server error
5xx Server Error
Server-side failures where the request was valid but the server could not complete it.
- 500Internal Server ErrorUnexpected server failure with no more specific code.
- 501Not ImplementedThe server does not support this functionality.
- 502Bad GatewayA gateway got an invalid response from upstream.
- 503Service UnavailableServer is overloaded or down for maintenance.
- 504Gateway TimeoutA gateway timed out waiting for upstream.
- 505HTTP Version Not SupportedThe HTTP version in the request is not supported.
- 506Variant Also NegotiatesContent negotiation is misconfigured into a loop.
- 507Insufficient StorageWebDAVWebDAV: the server is out of storage.
- 508Loop DetectedWebDAVWebDAV: the server hit an infinite loop while processing.
- 509Bandwidth Limit ExceededcPanelcPanel hosting: the administrator-imposed bandwidth limit was reached.
- 510Not ExtendedAn HTTP extension the request needs isn’t supported (historic).
- 511Network Authentication RequiredLog in to the network first, e.g. a captive Wi-Fi portal.
- 520Web Server Returned an Unknown ErrorCloudflareCloudflare: origin returned an unexpected response.
- 521Web Server Is DownCloudflareCloudflare: the origin server refused the connection.
- 522Connection Timed OutCloudflareCloudflare: connecting to the origin timed out.
- 523Origin Is UnreachableCloudflareCloudflare: the origin is unreachable.
- 524A Timeout OccurredCloudflareCloudflare: the origin accepted but replied too slowly.
- 525SSL Handshake FailedCloudflareCloudflare: the TLS handshake with the origin failed.
- 526Invalid SSL CertificateCloudflareCloudflare: the origin’s certificate failed strict validation.
- 529Site Is OverloadedSSL Labs / AnthropicSSL Labs / Anthropic: the API is temporarily overloaded.
- 530Origin DNS ErrorCloudflareCloudflare: origin error, paired with a 1xxx error code.
- 561UnauthorizedAWS ALBAWS ALB: the identity provider returned an error during authentication.
Explore Other Status Classes
- 4 codes
1xx Informational
Interim responses that indicate request progress before a final response is sent.
- 9 codes
2xx Success
Responses indicating the request was accepted and processed successfully.
- 7 codes
3xx Redirection
Responses that tell clients to perform additional actions, usually by following a new URL.
- 36 codes
4xx Client Error
Client-side request issues such as invalid syntax, missing resources, or permission failures.