My HUD MX2 works without any problems with my PC or laptop using USB connection. When I connect my Galaxy S6 and HUD MX2 by USB OTG cable, everything looks OK - indicator lits yellow and when I start playing music, indicator lits green. But there is no sound. It is the same without supply adaptor or with supply adaptor connected. I have Android 7 now and it was the same on Android 6 before. I have tried several OTG cables - without any success. Thanks a lot for any help.