Please "Forget the Device" on the app before performing the Factory Reset.
Open the Pura app and you will see the homepage where it shows two scents. From there, click on the three dots at the top right corner of the screen. This will lead you to a page that says "Overview" at the top. Then, click on the three dots at the top right corner again. Then, click "Forget Device" and this will delete the device from the app. Then, proceed to perform the Factory Reset: