For Xcode 11 and Big Sur I got an official email from Apple:
From your email I can tell that a possible reason for you seeing this error message is the fact you are on the live version of Xcode and the. Beta version of MacOS. What I would suggest doing is updating the the Xcode version so it will better communicate with the MacOS. Please see the below link for more information on Xcode 12 beta.
t45
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