１. If you are using a macOS device, click the search icon at the top right of your screen to open Spotlight. Type in Security and Privacy and select the System Preferences panel.
２. Click on Privacy and click Microphone. Then, ensure that Google Chrome is checked. If the checkbox is unchecked, click on it to allow Chrome to access your microphone.
３. For the access to take effect, click Quit & Reopen. This will automatically close all your existing Chrome tabs, including ClassDo, and reopen Chrome.