Cox box not starting with Samsung sound bar

I just connected my Sony tv to a Samsung HW-Q90N sound bar via the ACR port on both units.  I also connected the sound bar to an Apple tv and a Cox cable box.  All connections use HDMI cables.  The problem is the cable box does not work, no picture or sound when I turn off the sound bar and tv and turn the devices on at a later time.  I changed the inputs for the external devices, and only the Apple tv works.  The cable box will only work if I do a hard reset.  Any ideas?

thanks