Error handling

Check the HTTP status and code field. WordPress may reject a request during authentication or parameter validation before AAM’s handler runs, so error bodies vary by failure point.

{
  "code": "rest_invalid_argument",
  "message": "The supplied value is invalid.",
  "data": { "status": 400 }
}

This is a typical AAM handler error shape. A WordPress validation error may also include params and details under data.

AAM code	Status	What to check
`rest_invalid_argument`	400	Required parameter, type, enum, or ID format.
`rest_unauthorized`	401 or 406	Authentication, management capability, or rejected operation.
`rest_not_found`	404	Target resource or disabled route.
`rest_workflow_error`	409	A rule or WordPress state blocks the change.
`rest_unexpected_error`	500	Unexpected handler failure; inspect server logs.
`rest_insufficient_storage`	507	AAM could not persist a change.

This mapping comes from AAM’s REST service trait. WordPress may return its own codes, including rest_forbidden and rest_invalid_param. Use the HTTP status and check the returned resource or success field where available.