Quick post as always!
I was having a lot of trouble with my Audeze Mobius device not working when connecting to a particular laptop as it was working fine over Bluetooth and USB when connected to other devices.
The problem was that the system was recognizing that the Mobius was connected and everything was showing as that was the default device for sound and communications but still no sound!
After opening the Sounds panel and clicking on Test button, I got the Unable to play test tone.
After trying various things like changing the Audio service's Log On account and all, it was still not working.
Finally, I decided to roll back the Audio driver since the last update I was seeing was back in 2022.
I went into
Sounds -> Right Click Audeze Mobius -> General -> Properties (Under Controller Information) -> Change Settings With UAC (If you see this) -> Driver Tab -> Rollback Driver.
As soon as I did this, the audio started working!