The various reasons a purchase can fail.
See Also: IStoreListener.OnPurchaseFailed.
| PurchasingUnavailable | The system purchasing feature is unavailable. |
| ExistingPurchasePending | A purchase was already in progress when a new purchase was requested. |
| ProductUnavailable | The product is not available to purchase on the store. |
| SignatureInvalid | Signature validation of the purchase's receipt failed. |
| UserCancelled | The user opted to cancel rather than proceed with the purchase. |
| PaymentDeclined | There was a problem with the payment. |
| DuplicateTransaction | A duplicate transaction error when the transaction has already been completed successfully. |
| Unknown | A catch-all for unrecognized purchase problems. |