This is your issue, I believe:

urls.py

urlpatterns = [
  url('^', IndexView.as_view(), name='index')
]

landing/urls.py

urlpatterns = [
  url(r'^admin/', admin.site.urls),
  url('^.*', include("landing.urls"))  # Circular reference
]

You’re reloading landing.urls inside your include tag everytime you load landing/urls.py.

Did you mean for that line to be in urls.py? If so you’ll need to alter one or both so they don’t conflict (i.e. ^ and ^.* both match an empty string).