Hello, I’m investigating a persistent StoreKit 2 restoration issue in My Drop Music. I would appreciate help identifying the cause or collecting more useful diagnostics. Environment: iPhone 17, iOS 26.6.2 TestFlight version 6.22.60 (62260.12) Transaction environment: Sandbox Storefront: USA, currency: USD What works: Product.products(for:) returns both expected non-consumable products. The full-unlock product returns a price of USD 6.99. The free trial product returns a price of 0. Transaction.currentEntitlements returns verified transactions for both products, with no unverified transactions reported. The app recognizes full access. What fails: When I tap “Restore purchases,” AppStore.sync() fails with StoreKitError.unknown. An Apple authentication prompt appears during restoration, but the operation still fails after submitting credentials. Latest diagnostic output: My Drop Music 6.22.60 (62260.12) iOS 26.6.2 Storefront=USA; currency=USD AppStore.sync=failed Kind: StoreKitError.unknown Reference: StoreKit.StoreKitError:2 Before: cached app state: full=true; trialPresent=true After: full=1; trial=1; unverified=0; environment=Environment(rawValue: “Sandbox”) Tests already performed: Reproduced over both Wi-Fi and cellular. Signed out of and back into Media & Purchases. Modified the restoration flow so AppStore.sync() is the first awaited operation after the user taps Restore. Entitlement and storefront diagnostics are collected afterward. The failure persists. Created a separate Sandbox tester. Attempting authentication with that tester produced a system alert saying “Verification Failed — An unknown error occurred.” I have not established whether that is the same underlying issue. I currently have only one iPhone available for testing. Does this pattern suggest any specific account, device, or integration checks? Which device logs or additional error details would help distinguish a Sandbox authentication issue from an app integration issue? I am not assuming this is an Apple bug; I’m trying to determine the cause. Thank you!