CHW-4611 CachePurgePasswordRequired

cache purge-all requires a password in the request body

Default message: cache purge-all requires a password in the request body
HTTP status: 400 (client)

Problem. POST /api/cache/purge-all requires the caller’s password in the body and the field was empty. Cause. The request body was present but password was unset or blank. Fix. Resubmit with a non-empty password field. HTTP 400.