Deploying a python flask web application on Heroku with Windows
I was having the same problem. Particularly, waitress works locally in Windows (inside a Procfile.windows file web: waitress-serve index:server, then with heroku CLI heroku local -f Procfile.windows), but failed after Heroku deployment. Workaround for me was to locally test with waitress (like explained), but deploy with gunicorn (web: gunicorn index:server inside Procfile). Let me know if this works for you.
I am trying to deploy a flask app I made to Heroku with success.
The app is generated but I get errors when I push the code to the Heroku repository.
My flask app is inside a module called server.py and the variable is named app.
At first I tried using gunicorn and writing 
web: gunicorn server:app
and deplying but no web dynos were up and I get an error stating it is the Procfile file.
Red about it about and saw that Gunicorn is not really working on windows so I tried installing Waitress and deploying without success. this time my profcile was written as all of these (tried several times):
web: waitress-serve --listen=*:8000 server.wsgi:application
web: waitress-serve --listen=*:8000 app.wsgi:application
And so on.
to add a web dyno I should scale it because heroku ps: showes that there is no dynos.
When I try to run heroku ps:scale web=1 I get:
Scaling dynos... !
 ▸    Couldn't find that process type.
What am i doing wrong?