Order sync errors returned from QuickBooks
1. The List element is already in use
This is a common error returned by QuickBooks. For example, if a product named "Apple" exists in QuickBooks, but, it's inactive, then our app tries to create a new product because our app won't match the Shopify product with an inactive product in QuickBooks. Even though our app will try to create a new product QuickBooks has this validation that it won't allow creating a product with the same name, hence will return the above error. The same error can occur while syncing the customer. If the product or customer is not synced, then the order will also not sync to QuickBooks due to the above-mentioned error. You need to make sure that the products sold in an order and the customer associated with the order are not inactive in QuickBooks. If they are inactive then you either need to make them active or rename that product. After taking these actions you can attempt resync for the orders from our app dashboard in Shopify. Please follow the below navigation.
Shopify>>Apps>>QuickBooks Desktop>>Order List>>Unsynced Orders