The power for which device? Based on what you’ve posted, it seems as though the Arc is working properly, but your TV isn’t sending an appropriate signal to the Arc. Have you rebooted the TV? Have you contacted LG?

Thanks for responding. I took out both the power for the TV and the soundbar with no luck. I tried a new HDMI cable to make sure it wasn’t a cable issue.  I haven’t contacted LG yet as whenever I used the Set Up tv option in the Sonos app there is a notification on the TV that the HDMI used for ARC is available.  I thought that may be a sign that it’s trying to send the signal? The app read no connection though. Contacting LG is my next step.

Based on the information you’ve posted so far, it still seems questionable if the TV set is emitting a signal to the Sonos to play, but I suppose it’s also possible that the electronics have failed in the Sonos, those that are designed to receive the data. While you attempt to contact LG, it may also be worth submitting a system diagnostic within 10 minutes of experiencing this problem, and calling  Sonos Support to discuss it.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution. At the least, I hope they’d be able to tell if the Arc is receiving any signal at all, or if the electronics have failed in it. 

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

Appreciate all your insight on this!