Server Error HTTP Status Codes (5xx)

Use this hub during incidents to separate application crashes, gateway failures, overload, timeout conditions, and unsupported protocol handling.

What this group covers

5xx means the server or an upstream dependency failed to fulfill a request that was syntactically valid from the client perspective.

Start with request-correlated application logs and reverse-proxy logs.
Check dependency health (database, cache, third-party APIs) before retry storms spread.
Review deploy timeline and configuration changes around first error spike.

500 is generic app failure, 502/504 usually indicate upstream or gateway path issues, and 503 often indicates overload or maintenance mode.

HTTP 500 Internal Server Error — HTTP 500 Internal Server Error indicates a server errors response outcome.
HTTP 501 Not Implemented — HTTP 501 Not Implemented indicates a server errors response outcome.
HTTP 502 Bad Gateway — HTTP 502 Bad Gateway indicates a server errors response outcome.
HTTP 503 Service Unavailable — HTTP 503 Service Unavailable indicates a server errors response outcome.
HTTP 504 Gateway Timeout — HTTP 504 Gateway Timeout indicates a server errors response outcome.
HTTP 505 HTTP Version Not Supported — HTTP 505 HTTP Version Not Supported indicates a server errors response outcome.
HTTP 506 Variant Also Negotiates — HTTP 506 Variant Also Negotiates indicates a server errors response outcome.
HTTP 507 Insufficient Storage — HTTP 507 Insufficient Storage indicates a server errors response outcome.
HTTP 508 Loop Detected — HTTP 508 Loop Detected indicates a server errors response outcome.
HTTP 509 Unassigned — HTTP 509 is currently unassigned in the IANA registry and should not be emitted by modern applications.
HTTP 510 Not Extended — HTTP 510 Not Extended indicates a server errors response outcome.
HTTP 511 Network Authentication Required — HTTP 511 Network Authentication Required indicates a server errors response outcome.

Escalate when error rate crosses SLO thresholds, retries amplify load, or cross-region infrastructure components fail simultaneously.