no sound on netflix app

as per subject, not getting any sound on the netflix app. sound works on tv, recordings, live, other apps, works fine when I use the netfilx app on my smart TV, but nothing when I try to watch something on the netflix app on the X1.  works on the upstairs TV, which is the same model X1.  any ideas? I've already tried resetting the box, both soft reset and hard (power) reset same deal.