Troubleshooting: Why am I getting no audio input on macOS Mojave or Catalina?
Sound Studio requires microphone access for audio input, and you may have accidentally denied microphone access to Sound Studio. Granting microphone access is a new security feature in macOS Mojave and later (including Catalina).
To grant microphone access permission, go to System Preferences > Security & Privacy. Click on Microphone in the left pane and then check the box for Sound Studio to allow access.