Firefox 65.0.1 (64-bit) has suddenly stopped playing all HTML5 audio. (Videos play but there is no audio output.) Audio still works in Flash applications and HTML5 audio works as expected in other browsers.
I've tried disabling all of my extensions, restarting Firefox/the machine and the media output device listed in about:support looks correct.
Could anyone tell me how to fix this issue or how to go about debugging it?