Which server are you referring to, and what error are you receiving? Users can only purchase non-consumables and subscriptions once, regardless of receipt validation. This is enforced by the store API. Also, we are using purchaseToken now instead of transactionID as mentioned in the release notes Unity IAP package 4.12.2 is now available page-2#post-6434240 and Unity IAP package 4.12.2 is now available page-2#post-6506532