How to validate Streamlined Purchasing with storekit 2

users download app with Streamlined Purchasing ,but the logic of checking subscription doesn't work. there the code: func checkSubscriptionStatus() async { for await entitlement in Transaction.currentEntitlements { guard case .verified(let transaction) = entitlement else { continue } if transaction.productID == monthlyProductID || transaction.productID == yearlyProductID { if transaction.revocationDate == nil && !transaction.isUpgraded { let activeSubscribed = transaction.expirationDate ?? .distantFuture > .now if activeSubscribed { hasActiveSubscription = activeSubscribed // other operation } } } } }