How to fix the App Store after upgrading to macOS Catalina? Cannot open the App Store, after upgrading to macOS Catalina 10.15.3.

Things I have tried:


Reinstalled macOS Catalina.
Clearing cache and removing all the related folders as given at : How to fix / Reset App Store app on Mac OSX - El Capitan
What I have done is delete the App Store key chain entry in Finder, Application, Utilities, Keychain Access and the search for appstore. Delete just that one. (MacOS Catalina)