If your account is showing as Premium on one device but not the other, it means that you're not signed into the same account on both devices. Check your sign in by going to Settings > Account Settings and note the email address that's in use.
If you notice that you've skipped signing up on the app but created an account on the website, do the following to resolve the issue:
- Open the website and sign in.
- Navigate to Settings > Privacy Settings.
- Click Delete Account & Data to delete the account on the website, assuming you haven't added any data yet. You should be totally certain that there is no data in this account before deleting it.
- Open the app on your mobile device.
- From the left menu, select Create Account.
- Enter the email for the account you just deleted. Your app data will now be saved in an account.
- Return to the website and sign back in with the account you just created in the app.
Your data on the website will now be the same as the data on the app, and your Premium features will be found on both devices.