If Amazon rejects your cancellation request, the FBA/MCF fulfillment will not be cancelled through that request and may continue as planned. Shipr will notify you of the cancellation outcome and provide the available reason for the failure. You should review the notification and check the fulfillment status in Amazon Seller Central before taking further action.
The Shopify order cancellation setting applies only after Amazon successfully cancels the fulfillment. If Amazon rejects the request, Shipr will not perform the Shopify order status update associated with a successful cancellation.