This issue applies to Clearslide users who are running macOS Catalina (10.15) and are using Google Chrome.
Follow these steps to enable screen share:
1. Go to System Preferences, and click the "Security and Privacy" icon.
2. Click Screen Recording in the sidebar.
3. In the Screen Recording section click the box next to Google Chrome to allow screen sharing. And, unlock the small lock at the bottom of the window.
4. Click "Quit Now." You will not be able to screen share until you quit and restart Google Chrome.
5. Restart ClearSlide and you should now be able to screen share properly.
NOTE: Check the Chrome browser version and update it if necessary.