MacOS Big Sur - Wireless Casting with Vivi

Please ensure that you have enabled Screen Recording for Vivi by following the steps below.
Open the Launchpad (in the dock)
Search for "System Preferences" and launch it
Look for "Security and Privacy" and launch it
Ensure that Vivi has "Screen Recording" permission. While you're here, it's a good idea to scroll down and give it to other apps in the list!