I\'m at wit\'s end. After a dozen hours of troubleshooting, probably more, I thought I was finally in business, but then I got:
Model class django.contrib.co
I got this error also today. The Message referenced to some specific app of my apps in INSTALLED_APPS. But in fact it had nothing to do with this specific App. I used a new virtual Environment and forgot to install some Libraries, that i used in this project. After i installed the additional Libraries, it worked.