Server error
Generic 500 mapped to Server error. (AUTH / SERVER_ERROR). Example: unexpected exception in POST /api/auth/register after validation passed.
Why this happens
Unhandled server exception — DB outage, bug, or dependency failure. Not a validation, CSRF, or “registration disabled” message.
Diagnose and fix
1. Retry once; if it persists, check app logs around the failed request time.
2. Confirm database connectivity and disk/space on the app host.
3. Distinct from client Network error (request never completed) and from specific business errors.
4. After fixing infrastructure, retry register/login.