Why can't I turn off microphone settings on FB?? : r/facebook
How to Turn On Camera or Microphone on Facebook Messenger in Windows 10
Unable to access the microphone. Please check system settings." – Knowledge Base
How to Stop Facebook from Accessing Microphone on iPhone, iPad
Cleanfeed - If you're struggling with audio not working in Cleanfeed and you run Windows 10... you could be suffering from a small Windows 10 privacy setting preventing your microphone being used.
Think Facebook Is Spying on You? Turn Off Your Phone's Mic | Money