ImproperlyConfigured: The included URLconf does not appear to have any patterns

ImproperlyConfigured: URLconf empty or missing

$ python manage.py runserver
ImproperlyConfigured: The included URLconf 'project.urls' does not appear to have any patterns in it.

Why this happens

ROOT_URLCONF points to a module without urlpatterns or it’s empty.

Fix

Define urlpatterns with at least one pattern and ensure ROOT_URLCONF is correct.

Wrong code

# settings.py
ROOT_URLCONF = 'project.urls'
# project/urls.py
urlpatterns = []

Fixed code

# project/urls.py
from django.urls import path
urlpatterns = [
    path('health/', lambda r: HttpResponse('ok')),
]