Tracks stop playing after my Android device goes to sleep mode.

Inside of the Power Saving setting, you can Turn On Background Data. This lets you have many of the Power Saving benefits but continue streaming audio. To do this:

1. Launch Android settings
2. Select Wireless and Networks
3. Select Data Usage
4. Tap the 3DOTS on the top right
5. Tap 'Restrict Background Data' and disable it.