When first opening the app after installing on an Android device, you will be asked:  “Stop optimizing battery usage?”  Select “ALLOW“.

If you select “DENY”, when your device is not connected to a power source and you allow the screen to go dark, the app will stop playing music after 5 minutes of inactivity.  This is due to a battery-saving feature introduced by Android beginning with Version 6.  Selecting “ALLOW” lets the Radio Free Americana app run in the background, not restricting its battery usage.