We've got some Dell XPS13#9370 laptops, all of which are having an issue whereby the Cisco proximity application says "Your microphone is not working" even though you can see the audio levels go up and down on the microphone in the "recording devices" window.
Tried different drivers, BIOS update, Cisco Proximity 2.0.7 and 2.0.8 and installing Proximity straight from a fresh Win10 installation but no change.
Problem seems to be exactly the same as described in this thread:
Issues with Dell Latitude 5285 Proximity Application - Microphone not Working