After updating to the newest Mac OS update, screen sharing and audio permissions must be set in System Preferences.
Mac OS users will note, after updating to Catalina version 10.15 or later, they will be prompted to allow all media permissions and in some cases set specific system preferences to make use of sharing microphone, webcam, or screen. We recommend entering your first virtual class after this OS update early to ensure adequate time to enable all settings and restart your browser.
If the user denies the application permissions, the screen sharing or audio function will be disabled in the current and any future session until they enable this permission.
To access the permissions:
1. Open your Mac's Security & Privacy preferences.
2. Click the Privacy tab.
3. Click the Lock icon and enter your Mac credentials to make changes.
Here you can make changes for microphone, webcam, and screen recording.