If you made the full in-app purchase, you do not need to log in as the app will recognize your Apple or Google Play ID associated with the device. You may need to restore your purchase from within the app with the following steps.
- Click the menu on the top left corner of the app.
- Select "Purchase Full Content"
- Click "Restore Previous Purchase"
If you're still having issues, there is a workaround: restart your device and open the app. Then proceed within the app as if you are purchasing the content again for the first time. We know this sounds strange, but as long as you are using the same Apple or Google Play ID you used for the original purchase, Apple's system will recognize your prior purchase and you will not be charged twice.