Hello. My wife and I both purchased a ZTE Obsidian with Android 5.1.1 a couple of weeks ago. They work great, no problems at all - except for Spotify. Pretty randomly (sometimes when I open spotify, sometimes in the middle of a song, sometimes when switching songs or loading an ad) Spotify will completely hang/freeze up and will take my phone down with it. When this happens I can still see the Spotify interface on my screen but it has become completely unresponsive. If I try to switch programs or screens or go back to home screen so reset spotify - none of this works either - as my phone has completely frozen. Tried a reinstall twice (on both phones) and tried moving cache location to the phone to see if this helps - all without improvement. What am I doing wrong here??