Why am I getting a customer code is required error? Last updated 09:40, 9 Dec 2016 Save as PDF Overview You are receiving an error that says "CustomerCode is required". Environment Avalara Avatax Resolution The Customer Code is the unique identifier that is associated with the customer of an invoice/sales order/ quote. This is required since it is the key to the Exemption Certificate Management Service in the Admin Console. Please review your transaction to make sure that a customer is selected.