Cause
A reference in subjects does not exist in the company of the credential. Nothing is saved: the list is never left half-written. The response carries the subjects member with the references that failed, exactly as they were sent, and never product names or names of other entities. Resolving a catalog_item does not require the read:catalog scope.
What to do
Fix or remove the references the error lists and repeat the write.
application/problem+json
{
"type": "https://masnet.com/developers/errors/subject_unresolved",
"title": "Unresolved reference",
"status": 422,
"detail": "...",
"code": "subject_unresolved",
"correlation_id": "...",
"subjects": [
{
"kind": "catalog_item",
"external_id": "SKU-999"
}
]
}