From time to time I get this error on the browser “We are unable to access your microphone” (see attachment). This seems to be related to issues with the browser when you use other WebRTC services like Hangouts. I saw that Google handles this by providing an error message with an option to click (chrome://restart/) that restarts the browser and everything works fine afterwards.
Having that said I would like to be able to add that link to this message or intercept the event and display it some other way. I tried to look at the documentation but I could not find that event. I tried this one “audioAvailabilityChanged” without success.