Not working for me

[INGourav]

root@829e3edc10af:/opt# FLASK_APP=app.py flask run --host=0.0.0.0

• Serving Flask app 'app.py' (lazy loading)
• Environment: production
  WARNING: This is a development server. Do not use it in a production deployment.
  Use a production WSGI server instead.
• Debug mode: off
  Traceback (most recent call last):
  File "/usr/local/bin/flask", line 8, in
  sys.exit(main())
  File "/usr/local/lib/python3.8/dist-packages/flask/cli.py", line 990, in main
  cli.main(args=sys.argv[1:])
  File "/usr/local/lib/python3.8/dist-packages/flask/cli.py", line 596, in main
  return super().main(*args, **kwargs)
  File "/usr/local/lib/python3.8/dist-packages/click/core.py", line 1062, in main
  rv = self.invoke(ctx)
  File "/usr/local/lib/python3.8/dist-packages/click/core.py", line 1668, in invoke
  return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/local/lib/python3.8/dist-packages/click/core.py", line 1404, in invoke
  return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python3.8/dist-packages/click/core.py", line 763, in invoke
  return __callback(*args, **kwargs)
  File "/usr/local/lib/python3.8/dist-packages/click/decorators.py", line 84, in new_func
  return ctx.invoke(f, obj, *args, **kwargs)
  File "/usr/local/lib/python3.8/dist-packages/click/core.py", line 763, in invoke
  return __callback(*args, **kwargs)
  File "/usr/local/lib/python3.8/dist-packages/flask/cli.py", line 845, in run_command
  app = DispatchingApp(info.load_app, use_eager_loading=eager_loading)
  File "/usr/local/lib/python3.8/dist-packages/flask/cli.py", line 321, in init
  self._load_unlocked()
  File "/usr/local/lib/python3.8/dist-packages/flask/cli.py", line 346, in _load_unlocked
  self._app = rv = self.loader()
  File "/usr/local/lib/python3.8/dist-packages/flask/cli.py", line 402, in load_app
  app = locate_app(self, import_name, name)
  File "/usr/local/lib/python3.8/dist-packages/flask/cli.py", line 256, in locate_app
  import(module_name)
  File "/opt/app.py", line 9
  @app.route('/how are you')
  ^
  IndentationError: unindent does not match any outer indentation level

[sreelekshmi-Raj]

@INGourav Please try this solution
$ export FLASK_DEBUG=1
$ export FLASK_APP=app.py
$ export FLASK_ENV=development
Then start web server using
$ python3 -m flask run --host=0.0.0.0