It sounds rather like an issue with HDMI-CEC (protocol) - what TV are you using and besides the Sonos HT device being connected to its Arc/eARC port, do you have other devices connected to the other TV HDMI ports.

Also, it might be worth forcing that update for the TV’s software. I don’t think it shows up in the diagnostic what kind of TV, or what version of the CEC firmware it’s running, so making sure you’re on the latest from the manufacturer would be a good place to start. 

Thanks both,

it is a Samsung Frame 2019, and have updated it to latest firmware.

No other devices until today (installed a PlayStation 5 for the kids) and have tried rebooting/reinserting cables in different order etc but still same issue.

Best,

Patrik

That particular TV is mentioned in the community here as having some issues, but most folk appear to have resolved them by doing either of the following…

1. Disconnecting all the other devices from the TV, except the Sonos Arc and enabling HDMI-CEC/Anynet+ in TV Settings. Then powering all ‘off’ and then ‘on’ again and once it’s working, cable the other devices back to the TV - if by connecting a device, it causes an audio problem, then to switch off HDMI-CEC within the settings on that ‘other’ device - or uses a CEC-less adapter (available on the Amazon website and similar outlets).
2. Some Samsung Frame users mention that they have also had success with the Optical to HDMI adapter to the Arc with Anynet+ either switched ‘on’ or ‘off’ in the TV settings in that instance.

So perhaps give both options above a try and see if either may work for you.

In particular, this thread: