Django heroku : Unable to deploy application (ModuleNotFoundError) - django

Question

When I am deploying my Django application on Heroku, the application crash and Heroku's logs notify me about this error :
2020-12-07T12:55:55.982458+00:00 app[web.1]: ModuleNotFoundError: No module named 'WebSite'
The thing is, WebSite is not a Python module, but a folder in my Django application (Achievement Comparer being my main application name).
AchievementComparer/
AchievementComparer/ ← My Django project
static/
staticfiles/
WebSite/ ← A Django app
__init__.py
manage.py
wsgi.py
Procfile
requirements.txt
runtime.txt
Of course, if I start my application locally, everything works just fine (running py manage.py runserver on Windows, as gunicorn is only available on unix).

Answer 1

The current issue is that you have an extra directory layer:
AchievementComparer/ ← This shouldn't be here
AchievementComparer/
WebSite/
manage.py
…
Procfile
requirements.txt
runtime.txt
Move everything that's currently in the top-level AchievementComparer/ directory up a level and delete the now-empty old AchievementComparer/ directory:
AchievementComparer/
asgi.py
settings.py
wsgi.py
WebSite/
manage.py
Procfile
requirements.txt
runtime.txt
A few other issues that are likely to bite you next:
The only wsgi.py file you should need is the one that's currently in your AchievementComparer/ project directory, beside your settings.py. Delete the other one.
Your Procfile is hard-coding a port. You'll need to bind to whatever port Heroku assigns you via the PORT environment variable.
You don't need --pythonpath in your Procfile, but you should update the module to use the full module name AchievementComparer.wsgi.
All in all, try changing your Procfile to something like this:
web: gunicorn AchievementComparer.wsgi:application --bind=0.0.0.0:$PORT --log-file -