@matt3c Is this a new install or something that was working and now broke? On the sales order is the shipping address correct? While in Edit mode on the Sales Order there are two buttons AvaTax adds. One is "Validate Shipping Address". You might want to try that. If you have the right permissions to view it, there's a "AvaTax" tab on the sales order which show the SOAP logs. Might be something in there that will help you.