Why does my Django Project not recognize apps installed on the settings?

Question

I am trying to build my portfolio in Django and encountered an error after installing my app. It seems like it doesn't recognize the app on my INSTALLED_APPS. I've tried using 'blog' and 'blog.apps.BlogConfig' but nothing seems to be recognized.

I run the runserver with python manage.py runserver and python manage.py runserver but both returns ModuleNotFoundError: No module named 'blog.urls'

This is the whole traceback

Exception in thread django-main-thread:
Traceback (most recent call last):
  File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/threading.py", line 917, in _bootstrap_inner
    self.run()
  File "/usr/local/Cellar/python/3.7.3/Frameworks/Python.framework/Versions/3.7/lib/python3.7/threading.py", line 865, in run
    self._target(*self._args, **self._kwargs)
  File "/Users/usr/django-portfolio/env/lib/python3.7/site-packages/django/utils/autoreload.py", line 54, in wrapper
    fn(*args, **kwargs)
  File "/Users/usr/django-portfolio/env/lib/python3.7/site-packages/django/core/management/commands/runserver.py", line 117, in inner_run
    self.check(display_num_errors=True)
  File "/Users/usr/django-portfolio/env/lib/python3.7/site-packages/django/core/management/base.py", line 390, in check
    include_deployment_checks=include_deployment_checks,
  File "/Users/usr/django-portfolio/env/lib/python3.7/site-packages/django/core/management/base.py", line 377, in _run_checks
    return checks.run_checks(**kwargs)
  File "/Users/usr/django-portfolio/env/lib/python3.7/site-packages/django/core/checks/registry.py", line 72, in run_checks
    new_errors = check(app_configs=app_configs)
  File "/Users/usr/django-portfolio/env/lib/python3.7/site-packages/django/core/checks/urls.py", line 13, in check_url_config
    return check_resolver(resolver)
  File "/Users/usr/django-portfolio/env/lib/python3.7/site-packages/django/core/checks/urls.py", line 23, in check_resolver
    return check_method()
  File "/Users/usr/django-portfolio/env/lib/python3.7/site-packages/django/urls/resolvers.py", line 398, in check
    for pattern in self.url_patterns:
  File "/Users/usr/django-portfolio/env/lib/python3.7/site-packages/django/utils/functional.py", line 80, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/Users/usr/django-portfolio/env/lib/python3.7/site-packages/django/urls/resolvers.py", line 579, in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "/Users/usr/django-portfolio/env/lib/python3.7/site-packages/django/utils/functional.py", line 80, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "/Users/usr/django-portfolio/env/lib/python3.7/site-packages/django/urls/resolvers.py", line 572, in urlconf_module
    return import_module(self.urlconf_name)
  File "/Users/usr/django-portfolio/env/lib/python3.7/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 967, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 677, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 728, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "/Users/usr/django-portfolio/portfolio/portfolio/urls.py", line 21, in <module>
    path('', include('blog.urls'))
  File "/Users/usr/django-portfolio/env/lib/python3.7/site-packages/django/urls/conf.py", line 34, in include
    urlconf_module = import_module(urlconf_module)
  File "/Users/usr/django-portfolio/env/lib/python3.7/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1006, in _gcd_import
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 965, in _find_and_load_unlocked
ModuleNotFoundError: No module named 'blog.urls'

My INSTALLED_APPS is

INSTALLED_APPS = [
....
'blog'
]

URL in Settings

 from django.contrib import admin
 from django.urls import path, include

 urlpatterns = [
     path('admin/', admin.site.urls),
     path('', include('blog.urls'))
 ]

Answer 1

Make sure you have structured your blog app and parent app properly. And you module path is set properly. For reference you can also see Django Installed Apps Location

Answer 2

No module named 'blog.urls' means you don't have urls module inside blog.

You need to create a file named urls.py inside the blog app. And you need to define some routes there.

After that below line

 path('', include('blog.urls'))

will work fine.