Label not found

Check the identifier. A project's own labels are not visible from another project; platform-wide ones are visible from all of them.

The body is application/problem+json. detail varies with the request; everything else is what you see here.

{
  "type": "https://docs.rsx.group/errors/label-not-found",
  "title": "Label not found",
  "status": 404,
  "detail": "...",
  "instance": "/{project}/{version}/{group}/{action}",
  "requestId": "0198f2b1-..."
}