Why am I getting a "Customer Code is prohibited based on the Event Type/Document Control Options (A226)" error on my document?

Customer Code is prohibited based on Event Type/Document Control options. If this error is received and Vendor Code was entered, the Vendor Status was not Active but the Customer Status was Active. To process with the Vendor Code, it must be in Active status. You will want to contact CAVO (state_centralapproval@state.co.us) for further assistance.