What fixed it for me was: Close Xcode Delete those folders: ~/Library/Caches/org.swift.swiftpm ~/Library/Developer/Xcode/DerivedData Restart Xcode Right click and "update package"

Here's the Swift version: func paymentQueue(_ queue: SKPaymentQueue, shouldAddStorePayment payment: SKPayment, for product: SKProduct) -> Bool { return true }

Hey there, We also see this error on some of our purchases - but only in failed transactions. What is the reason for this error and how can it be prevented?