Prior to 3.x, django-registration installed a Python module named registration. To avoid silent incompatibilities, and to conform to more recent best practices, django-registration 3.x now installs a module named django_registration.
So the templates directory of this project is registration, but it now should be django_registration
https://django-registration.readthedocs.io/en/3.0/upgrade.html says:
Prior to 3.x, django-registration installed a Python module named registration. To avoid silent incompatibilities, and to conform to more recent best practices, django-registration 3.x now installs a module named django_registration.
So the templates directory of this project is
registration
, but it now should bedjango_registration