Duolingo is, sometimes, not recognizing my microphone. I have checked three times: that my computer is working correctly; that the integrated microphone is working; that I have set Duolingo settings to "microphone ON"; that my internet connection is working, and powerful… and still, most of the time Duolingo gives the option to speak to the microphone but it doesn't receive the sound. PLEASE HELP. It is very annoying.