ModuleNotFoundError: No module named 'grp' on windows
If you're using the PyPi package django-celery-beat it looks like it installs the most recent version of the required package celery rather than installing a compatible version (by the time I'm posting this, 25th of May 2021 this would be v5.1.0), which seems to have compatibility issues with django-celery-beat version 2.2.0 (the most recent) as well as Windows OS.
I suggest you try
pip uninstall celerypip install celery==5.0.5