If you are unable to access your subscription on the device that you purchased it, please tap on the "Restore" button in the app to unlock previous purchases again.
This will work if you are using the same account with which you made the purchase.
To share your subscription on another device, please follow the steps -
Open Kiddopia on the device that you purchased it.
Tap on the Settings icon.
Here tap on Sign In and follow the instructions.
Once you have signed in, please follow these steps on the devices that you’d like to share the app using the same account to sign in that you used above.