I use spotify, and I haven't been able to get it to work on my new LG v60 think.
I tried rebooting, reinstalling, then uninstalling Poweramp and spotify and reinstalling both. Nothing seems to work. I have had my phone booted for one day so the few minute.
I can see in the EQ scroll bar that audio is coming through, but moving the EQ sliders, bass/treble knobs, gain doesn't change anything.