I am using StoreKit for in-app purchases. I'm testing the restoration of a purchase, to no avail. I keep getting this error message after typing in the username & password for a sandbox tester: Error Domain=SKErrorDomain Code=0 "UNKNOWN_ERROR" UserInfo={NSLocalizedDescription=UNKNOWN_ERROR, NSUnderlyingError=0x7b0c000652b0 {Error Domain=ASDErrorDomain Code=500 "Unhandled exception" UserInfo={NSUnderlyingError=0x7b0c00079ef0 {Error Domain=AMSErrorDomain Code=100 "Authentication Failed" UserInfo={NSLocalizedFailureReason=The verify credentials call failed., NSLocalizedDescription=Authentication Failed, NSUnderlyingError=0x7b0c0007fbc0 {Error Domain=AMSErrorDomain Code=15 "An unknown error occurred. Please try again." UserInfo=0x7b0800027540 (not displayed)}}}, NSLocalizedFailureReason=An unknown error occurred, NSLocalizedDescription=Unhandled exception}}} What do I need to do to resolve this error?

I have an app that's in the App Store and that has been installed by hundreds of people. I'm planning to convert my codebase to use React Native/TypeScript and then publish this new version to the App Store as an update. There may be existing users with data that is stored via Core Data/SQLite, and I want to try to ensure that their data will still be visible in the application when they install the update. How do I do that?

I have a Website live on http://chatwithsanta.azurewebsites.net/ It uses Flexbox to show chat messages and a chat message input. Specifically, the Body is a flexbox container with a message screen containing messages, and a message input form at the bottom. This layout works in Chrome on desktop, even when Chrome is set to simulate an iPhone 12 Pro layout. But the form does not appear on my own iPhone. What should I do?