It’s possible that the CEC system on the TV isn’t properly recognizing the fact that the Beam is connected via ARC. I’d do a few things, to be certain. First, I’d research the HDMI cable both in the Beam, and in the TV’s ARC port. And honestly, if you have another HDMI cable, I’d test that too. HDMI cables are definitely more sturdy than optical cables, but they can still fail sometimes. 

Then I’d try unplugging the TV from the wall for two or three minutes, before plugging it back in. You’re trying to force a reload of the software running all the TV’s systems, something that doesn’t occur if you turn it off with the remote, or a power button on the TV. 

Hi Alex0606, did you manage to fix this? I have the same problem also overnight, probably since last Sonos update to 14.2. It worked for months, I did not change anything, and suddenly no sound from TV anymore. Please let me know if and how you fixed it.

Thanks!

Try rebooting your TV (full power down by unplugging it from the wall for two minutes) as well as a reboot of your Beam. 

Thanks Airgetlam, I’ve been doing nothing else for several hours a day since Saturday, together with HDfury tech support (since I use the Arcana). This does not work, the only way I can get the Braviasync device list on my Sony TV populated (with the Beam and/or my Apple TV 4K) is by plugging it in directly. I can then plug it over to the arcana, and things work, but as soon as I change from TV audio back to one of the HDMI inputs that input will work, but Braviasync list turns up empty, and if I switch back to TV channel sound is lost again. Setting up the Beam with the Sonos up fails every time after that. This has worked for months, the only thing that changed since last week is that I approved the latest Sonos update. So I’m trying to find out if more Sonos users experience ARC (audio return) problems since the last Sonos update, found a couple already in forums, including (as it seems to me) Alex0606. So please @Alex0606 please confirm your problem is solved or not, thanks.