Keep getting this error when pushing orders to QuickBooks Desktop using MyWorks Sync?

Error

Error Number:3140

Error:There is an invalid reference to QuickBooks Item "" in the Invoice line.

Causes

1. A default unmatched product, shipping, or coupon setting is not set in MyWorks Sync > Settings > Defaults.
2. A product in the WooCommerce order is not mapped in MyWorks Sync > Map > Products.
3. A QuickBooks product for a custom fee line item is not yet set at MyWorks Sync > Compatibility > WooCommerce Order Fee Line Items (if a custom fee line item is being used in the corresponding order)

Resolution

Ensure that all Default Settings are set.

1. Visit MyWorks Sync > Settings > Defaults.
2. Make sure that all dropdowns in this tab are correctly set, and not left blank.

Ensure that your products are mapped.

1. Visit MyWorks Sync > Map > Products.
2. Make sure all products that are in both WooCommerce and QuickBooks are correctly mapped here. If a product in the correspondingWooCommerce order is not mapped on this page, it can either be pushed to QuickBooks - or - if the "Default for Unmatched Products" setting is set above in MyWorks Sync > Settings > Defaults, the mapping can be left blank if it's not desired to map it to a specific QuickBooks product.

Ensure that a product for the fee line item is set.

1. Visit MyWorks Sync > Compatibility.
2. Make sure that there is a QuickBooks product set for the fee line item if the WooCommerce Order Fee Line Items is enabled, and not left blank.