I just buy this code Today. Codersboy team is very kind. He help a lot to solve my problem. The way to solve is different unity version and Plugins version. Just delete folder Asset/Plugins/UnityPurchasing. All done. The coding is very easy to read and document is very good with youtube. And It is very easy to use this code. Great Work Codersboy. I recomment to buy this item. Five Stars Quality.