CAPABILITY_NOT_SUPPORTED
HTTP 501No
The selected vendor does not implement this capability (e.g. maxmind/sift have no OFAC; sift/castle/maxmind have no KYC). Route to a vendor that supports it.
By default a failed call returns a result with an error instead of throwing, so your business flow is never interrupted.
Published error codes are permanent: their meaning never silently changes, and deprecated codes keep returning for at least 12 months.