macOS Catalina introduced new security features, and as a result you may need to update your System Preferences to allow screen sharing with doxy.me in your browser. (At this time it is not possible to screen share from mobile devices like a phone or a tablet.)
How to enable screen sharing
Open System Preferences (cmd + space)
Open Security & Privacy and scroll down to Screen Recording
Make sure your preferred browser is checked, and you'll be prompted to restart the browser.
If you have any questions, please contact our support team.