I had this exact same issue with my new set up back in May. The AVR even has an ARC light lit up that tells you it is receiving the audio return channel signal yet no sound. The key for my AVR is that it requires a one time 'soft reset' when setting up ARC. That simply meant I had to unplug and replug the AVR back in and shut the tv off then back on. It has worked ever since then. ARC is fantastic for utilizing the smart apps in the TV such as Netflix, etc. Some TV's however won't output 5.1 from their onboard apps, luckily mine did because I had no clue to even consider that when I bought all the gear.