Symptom:
During submission to eBay, the user gets a "(12024) Invalid Product Identifier" error.
Background:
eBay allows users to send UPC/ISBN/EAC/MPN information as part of the listing. This is used to more uniquely identify an item to buyers. This information is sent from SixBit by placing the UPC/ISBN/EAN/MPN in the ProductID field and then setting the ProductID Type (just to the right of the ProductID field) to either UPC/ISBN/EAC/MPN/None.
Cause:
You have chosen a ProductID type to go along with your ProductID, but when sent with your listing, eBay does not recognize the ProductID as a unique identifier of that type.
Solution:
To fix this, simply set the ProductID Type to "None".
