Specifying country codes for the Vertex tax system

If your customer or vendor tax code on the Tax Systems form is set to EXTRNL and your tax system on the Tax Interface Parameters form is set to Vertex, then you must specify default country codes in the US Country and Canada Country fields on the Vertex Parameters tab of the Tax Interface Parameters form. If these fields are not specified, an error is displayed on the portal when a user tries to register a new customer.