The main reason for the error was that python was a different location and other required applications were in different location.
if incase you have installed in other locations, first do an pip uninstall as follows
C:/ :pip uninstall django==4.0.2
C:/ :pip uninstall mssql-django, etc…
Use C:\Python> for installating Python and then use the same location for other pip installation:
ie.,
C:\Python> pip install django==4.0.2
C:\Python> pip install msql-django
C:\Python> pip install wfastcgi, etc…