This error may happen when there is not enough free space on your device. After freeing some space, restart the device, and launch the application.
On iOS, this error occurs when the application is launched after restoring from an unencrypted backup. By default, neither iTunes nor iCloud encrypt backups, so the key needed to decrypt the app database is not included in the restoration process. Make sure you always make encrypted back-ups on Apple devices.
If the application is still available on your “old” device, you can transfer your account from the “old” device to the “new” one :
