The flask command is separate from the flask.run method. It doesn’t see the app or its configuration. To change the host and port, pass them as options to the command.
flask run -h localhost -p 3000
Pass --help for the full list of options.
Setting the SERVER_NAME config will not affect the command either, as the command can’t see the app’s config.
Never expose the dev server to the outside (such as binding to 0.0.0.0). Use a production WSGI server such as uWSGI or Gunicorn.
gunicorn -w 2 -b 0.0.0.0:3000 myapp:app