Source: Bria Support Center
OS X Catalina and later require that you give permission to Bria for Screen Recording capabilities. Catalina should ask you to grant Screen Recording permission when first starting Screen Share.
If you experience unexpected issues when using Screen Share, check whether you have granted the permission to the app in OS System Preferences > Security & Privacy > Screen Recording. After granting permissions, restart the app.
If permissions is already granted but restarting the app doesn't help, try toggling it off and on again.