The order says unable to reserve inventory
Sometimes, you come across a situation where in the order section, you happen to have a status as “Error” and a message as “Order not created on Shopify”.
This type of situation arises when your order placed does not contain any inventory in your Shopify store.
For this, you simply can add your inventory in your Shopify store for the product. Doing so would automatically show the orders in your app.