I can't activate my Pro subscription on another device. Why not?

It is possible to activate your Pro subscription across multiple devices.  However, there are some steps to follow in order to do this properly.  Please note that there are two ways you could have initially purchased Pro:

1. You downloaded the free version from the Google Play store and then upgraded to Pro through the app.

2. You downloaded the Pro version from the Google Play store. 

In order to install Pro on another device, such as a new phone, you must follow the exact same process as when you initially purchased Pro.  For example, if you purchased Pro by downloading the free version from the Google Play store and then upgraded once inside the app, please do the same on your new device and it will upgrade automatically.  Also remember to login using the same account that you initially purchased Pro.