@john_couger, please provide some context and further information about the problem.
Furthermore, note that ARC only works with mobile phones or DACs connected directly to a Lightning or USB-C connector. The CXN should be used with Roon Remote, not Roon ARC.
I have an opticalrendu connected to Cambridge Audio CXN 2 usb port. The audio device that shows up as connected to the core (sonictransporter I5) is HDA Intel PCH AL662 Rev3 analog. Think I accidently went into settings and assigned this as sonore opticalrendu. Now I cant get any sound and everything worked great until I updated roon to 2.8 and updated the opticalrendu with updated software card.
The opticalRendu is a Roon Ready network device and not connected directly to your Core. I suggest you return the device named “opticalrendu to its original setting, and disable this in Roon.
Then enable the Sonore opticalRendu under Roon Ready.
Incidently, the CXN is Roon Ready, too, so you could enable this and connect it directly to your network.