An error that is returned when the specified container is unknown or unauthorized.
- iOS 8.0+
- macOS 10.10+
- UIKit for Mac 13.0+Beta
- tvOS 9.0+
- watchOS 3.0+
- Xcode 8.0+
This error should happen only during initial development of an app.
Double-check your app's CloudKit entitlements in Xcode and your container settings in the iCloud Dashboard.