Hello Kenneth Epstein,
Thanks for asking the Apple Support Communities for help with screen sharing.
Please start by turning all the screen sharing settings off. Turn Mac screen sharing on or off - Apple Support
Then, restart both computers. How to turn your Mac on or off - Apple Support
Once restarted, use the first article and re-enable all the settings. Please ensure you follow the steps from the article as the above article is specific to macOS Catalina.
Then, you can try setting up another screen sharing session: Share the screen of another Mac - Apple Support
Thanks and have a wonderful day.