Processes in Microsoft 365 Insider for installing preview builds, activating subscriptions, and keeping apps up to date with the latest Insider features.
I had the same problem running Big Sur. In my case, I have just changed licensing company after changing jobs, so that may be the reason for the problems. I followed @TobiasHammarstrand's suggestion of using the "License removal tool" and then reactivate Microsoft 365, and voila - it worked!
This worked for me.