content_blocked

Revise content or sender reputation. Do not suppress the destination as dead.

{
  "object": "event",
  "type": "message.failed",
  "livemode": true,
  "data": {
    "object": "message",
    "message_id": "msg_uuid",
    "status": "failed",
    "delivery_error_code": "content_blocked",
    "error_message": "The message was blocked as spam, content, or policy — not proof the number is dead."
  }
}