The accepted values for the attribute.

The attribute accepts free text (no list to enumerate; message only) or the attribute key is unrecognized (framework-shaped). Check valueFormat first.

The API key was missing or not accepted. Not JSON — a bare text/plain string: api key not provided, invalid api key, or invalid api key syntax.

The key is valid but not permitted: {"message": "Partner not authorized for this API"} or {"message": "Insufficient scope"}. Checked before body validation — even with ?dryRun=true.

Sovrn could not reach the downstream deal system; nothing was persisted — safe to retry with a unique name. Carries a required upstream field.