[Answered ]-How can I fix a 'ModuleNotFoundError' in django python?

There is no need.

'authentication.apps.AuthenticationConfig',
'orders.apps.OrdersConfig'

just add app_name

INSTALLED_APPS = [
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',

'authentication',
'orders',]

And Why you use python manage.py startapp authentication this code again. You already have authentication app in your folder.

well, to solve the problem I changed the location of the authentication folder :

I put it in the project folder.