Problem in Django 2.2 with Debug=True on Ubuntu - django

Question

I am trying to run a project in Django 2.2 with Debug=True on Ubuntu but I get this error in python manager.py runserver:
Exception in thread django-main-thread:
Traceback (most recent call last):
File "/usr/local/lib/python3.5/dist-packages/django/urls/resolvers.py", line 581, in url_patterns
iter(patterns)
TypeError: 'module' object is not iterable
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/lib/python3.5/threading.py", line 914, in _bootstrap_inner
self.run()
File "/usr/lib/python3.5/threading.py", line 862, in run
self._target(*self._args, **self._kwargs)
File "/usr/local/lib/python3.5/dist-packages/django/utils/autoreload.py", line 54, in wrapper
fn(*args, **kwargs)
File "/usr/local/lib/python3.5/dist-packages/django/core/management/commands/runserver.py", line 117, in inner_run
self.check(display_num_errors=True)
File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 390, in check
include_deployment_checks=include_deployment_checks,
File "/usr/local/lib/python3.5/dist-packages/django/core/management/base.py", line 377, in _run_checks
return checks.run_checks(**kwargs)
File "/usr/local/lib/python3.5/dist-packages/django/core/checks/registry.py", line 72, in run_checks
new_errors = check(app_configs=app_configs)
File "/usr/local/lib/python3.5/dist-packages/django/core/checks/urls.py", line 40, in check_url_namespaces_unique
all_namespaces = _load_all_namespaces(resolver)
File "/usr/local/lib/python3.5/dist-packages/django/core/checks/urls.py", line 57, in _load_all_namespaces
url_patterns = getattr(resolver, 'url_patterns', [])
File "/usr/local/lib/python3.5/dist-packages/django/utils/functional.py", line 80, in __get__
res = instance.__dict__[self.name] = self.func(instance)
File "/usr/local/lib/python3.5/dist-packages/django/urls/resolvers.py", line 588, in url_patterns
raise ImproperlyConfigured(msg.format(name=self.urlconf_name))
django.core.exceptions.ImproperlyConfigured: The included URLconf 'moeaforhdl.urls' does not appear to have any patterns in it. If you see valid patterns in the file then the issue is probably caused by a circular import.
This is /myparentapp/urls.py:
from django.conf.urls import include, url
from django.contrib import admin
from django.conf import settings
from django.conf.urls.static import static
urlpatterns = [
url(r'', include('moeaforhdlweb.urls')),
url(r'^admin/', admin.site.urls),
url(r'^tinymce/', include('tinymce.urls'))
]
if settings.DEBUG:
urlpatterns += static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)
This is /mychildapp/urls.py:
from django.conf.urls import url
from . import views
from django.conf import settings
from django.conf.urls.static import static
urlpatterns = [
url(r'^$', views.index, name='index'),
url(r'^help/$', views.help, name='help')
] + static(settings.STATIC_URL, document_root=settings.STATIC_ROOT)
I test this project on Windows 10 and it works perfectly, but not on Ubuntu.
Besides, if I comment this line:
url(r'', include('moeaforhdlweb.urls'))
it works.
Any help will be grateful, thanks a lot.