In the AppStore Connect for an iOS-app, I have an auto-renewable subscription group with two subscriptions at the same level 1.
In a Sandbox mode, I've purchased one of the subscriptions from the group and then have tried to buy another one making a crossgrade.
The first one I've succeeded to purchase, but on the second payment I've got an error inside func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]):
Error Domain=SSServerErrorDomain Code=3720 "You’re all set" UserInfo={NSLocalizedDescription=You’re all set}
Also, for the second purchase in the app, there was a Sandbox-alert:
"You're all set
Your purchase was successful"
Why am I getting this error and what does it mean?