Why is my Shopify orders' status not getting changed from unfulfilled to Fulfilled?

Why is my Shopify orders' status not getting changed from unfulfilled to Fulfilled?

If the App: Amazon MCF by WebBee is correctly configured,
then as soon as an order shows a "Complete" status inside Amazon Seller Central (below is a screenshot), within 2-3 hours, our app will automatically change the status of it to "Fulfilled" inside Shopify as well.




Note: If an order has been "accepted by Amazon" in our app. 
It means that this order is in planning/ in processing (pick, pack and ship) at Amazon FBA warehouse.
As soon as this is complete at Amazon it will start showing at Shopify as fulfilled.
However, before that the order would be marked as unfulfilled at Shopify.

In case, you have any questions OR need some assistance, you can always reach out to us at help@webbeeglobal.com.