I suspect there’s an issue with the CEC controller in your TV not appropriate recognizing the connected client (the Sonos). I’d certainly do two things. First, check your TV for any software updates, and apply them. Once you’ve done that, unplug the TV from the wall for 5 minutes, then plug it back in. This will force the OS (and CEC) to reboot and reload, and should hopefully resolve the issue.

It wouldn’t hurt to power down the Arc and reboot it as well, although the chances of it being the Arc itself are relatively low, it is, as I’ve said, merely a “client” device, connecting to a computer in your TV that runs the CEC system.

Thanks for your reply.  My TV software is always up to date as I use the automatic update feature. I checked just in case and no upgrades are available so I guess that means I am current. My ARC and TV are plugged into the same outlet so when I unplug the power its both the TV and ARC that are reset. I have not been waiting 5 minutes so I will try that.