When I attempt to purchase the premium version of the application, I receive the error message "Internet Connection Required".
I am running a rooted nexus 5 (Hammerhead) running Android 6.0 build # M8974A. I'm in the US on T-Mobile. I'm able to use all other data-related functions on the device. This is not specific to a location or connection type and occurs on all forms of cellular data connections with countless different cell towers and also occurs on all WiFi connections.