To make a non-taxable customer compatible with RouteStar please ensure the customer is assigned a 0% tax rate within QuickBooks by following the steps below.
Open/Edit the non-taxable customer in QuickBooks and navigate to the Sales Tax tab.
Ensure the Tax Code is set to Non.
Next we need to set the Tax Item to one that is set to exempt or 0%.
If you don't see a tax item already created for this purpose go ahead and select <Add New> at the top and create a new sales tax item set to 0%.