“No sound when I stream Netflix through my AV receiver” seems to be a common unsolved issue. I was having this problem, and started messing with my device. I had my ARC HDMI cable plugged in, and I even had an optical connection, but nothing. I tried the suggestions given and still nothing. I tried messing around with the “initial setup menu” on the receiver and found that there was a setting in my device (ONKYO) where you had to actually turn on the ARC feature, that just plugging in the cable wasn’t enough. Once I did this, the sound was fine. Just thought I would pass this along.