HTTP 500 Internal Server Error

The application itself raised an error. The server is up; something inside it failed.

What it usually means

The application itself raised an error. The server is up; something inside it failed. Your application logs will have the traceback.

What to check first

The application log for the traceback at the time of the check.
A deploy, a configuration change or a dependency (database, cache, third-party API) that started failing.
Disk space and memory: a full disk produces 500s long before the server goes down.

How ErrorDetector reports it

The target answered, so this is reported as a failed check, not downtime: the alert names the reason, the uptime percentage is untouched, and a recovery notice follows when the check passes again.

Caught by: httpkeywordapi monitors. Read about the incident management feature.

Get the cause, not a red dot

Ten monitors free, no card, no time limit. Every incident names the failure.

Start monitoring free

Other causes

DNS · DNS resolution failed (NXDOMAIN, no answer) REF · Connection refused TLS · TLS handshake failed (certificate error) RST · Connection reset by peer NET · Host unreachable (no route) T/O · Connection timed out RDR · Redirect loop (too many redirects) KEY · Keyword not found on the page SLOW · Response slower than the limit ASSERT · API response failed its body assertion BLK · Blocked by a firewall or bot filter 401 · HTTP 401 Unauthorized 403 · HTTP 403 Forbidden 404 · HTTP 404 Not Found 429 · HTTP 429 Too Many Requests 502 · HTTP 502 Bad Gateway 503 · HTTP 503 Service Unavailable 504 · HTTP 504 Gateway Timeout