Set the Digital Output Audio Format setting on the TV to Pass-Through, not Auto.
And if you are only using the TV’s native apps, set the HDMI-eARC Mode setting to OFF.
Hi we have tried that and it didn't work sadly :(
Use the TV settings I mentioned above and try this:
Disconnect everything from the TV and unplug the Arc and TV from power for a couple of minutes. Plug everything back in but keep everything disconnected. Make sure Anynet+ is enabled in the TV settings. Run TV Setup in the Sonos app and follow the app instructions. When the app instructs you, connect the Arc to the TV’s HDMI ARC/eARC port using the Sonos-supplied HDMI cable. After the Arc has been successfully connected, connect any other devices to the TV.