starting from macOS Mojave 10.14, apps no longer have access to the microphone or other audio input devices unless you specifically "allow" each app to use the microphone or other audio input devices.
when the app gets launched for the first time, macOS will ask you whether it's okay for the app to use the microphone. if you don't allow, ProPhase/ProPhase won't be able to monitor any audio inputs.
if you for some reason missed or macOS didn't show you the microphone usage window, you can open the System Preferences app and allow the microphone usage in the Privacy tab on the Security & Privacy pref pane.
