As long as the TV is sending nothing higher that Dolby Digital through to the adapter, and the adapter is sending on that signal to the PLAYBAR, it should be working. 

The PLAYBAR (and optical cable) can’t handle anything above Dolby digital (5.1). 

If you’re still having issues, perhaps more details about the TV and adapter may be helpful, or you could call Sonos Support directly to discuss 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.

Hi

Sonos doesn't work with an adapter. The Tv has to have an optical port

Hopefully you mean an hdmi to optical audio extractor, the sonos hdmi to optical will not work with playbar

In most cases, when using an optical connection device such as a PLAYBAR, these days, the audio is pulled off of the HDMI signal from the HDMI input before it reaches the TV set, using a fairly standard and inexpensive HDMI switch that has an optical output. This does remove the possibility of using the internal apps of the TV itself, unfortunately, but works well for any external devices connected to the TV set.