ModuleNotFoundError in PyCharm

[Friedrich Buetefuer]

I've installed grappelli using: pip install django-grappelli

After adding 'grappelli' to my INSTALLED_APPS my application won't start. It dies with the error message: (<class 'ModuleNotFoundError'>, ModuleNotFoundError("No module named 'grappelli'"), <traceback object at 0x000001ECD665AA00>)

I'm using PyCharm Professional 2020.3.3 and django (3, 1, 4, 'final', 0) on python3: 3.8.6 on Windows10 64bit

I've googled and found similar problems, but no solution. I've tried restarting everything, and even manually copied the django_grappelli-2.14.3.dist-info directory into my virtual environment.

Does anybody know what I am doing wrong?

Thanks

Fred