You can't set taxable if Sales tax is turned off or the item is not a taxable item type.

Enable sales tax in QuickBooks

Problem

Your sales fail to sync and you get this error:

Error 3140 : There is an invalid reference to QuickBooks InvoiceLineItem SalesTaxCode "Tax" in the Invoice line. QuickBooks error message: You can't set taxable if Sales tax is turned off or the item is not a taxable item type.

Description

Connex is trying to apply tax, but sales tax is disabled in QuickBooks.

Solution

Enable sales tax in QuickBooks:

1. In QuickBooks, go to edit > preferences > sales tax.
2. Enable tax:
3. In most common item, create a new item called out of state:
4. Click OK to save the vendor.
5. Click OK to save the changes.