Looking into your app and sandbox account. You don't have a production account and your app is a private app. That is why you cannot graduate the app to the production environment due to no production account.

If you intend to make this app available to other RingCentral users, you have to change the app from private to public.

If you have a production account, then the sandbox account you are working on is not an associated sandbox account with your production account. Then you have to login your associated account and create a new app under that sandbox account. Then test and graduate the new app.