My dash app works well on my localhost, but when it got hosted on Heroku, the scatter line plot is not displaying and my css design added through an assets folder outside the app.py file can’t be displayed.
This the logs from heroku logs --tail.
[2019-10-01 09:14:08,943] ERROR in app: Exception on /_dash-update-component [POST]
2019-10-01T09:14:08.943971+00:00 app[web.1]: Traceback (most recent call last):
2019-10-01T09:14:08.943973+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.6/site-packages/flask/app.py", line 2446, in wsgi_app
2019-10-01T09:14:08.943976+00:00 app[web.1]: response = self.full_dispatch_request()
2019-10-01T09:14:08.943978+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.6/site-packages/flask/app.py", line 1951, in full_dispatch_request
2019-10-01T09:14:08.943981+00:00 app[web.1]: rv = self.handle_user_exception(e)
2019-10-01T09:14:08.943983+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.6/site-packages/flask/app.py", line 1820, in handle_user_exception
2019-10-01T09:14:08.944005+00:00 app[web.1]: reraise(exc_type, exc_value, tb)
2019-10-01T09:14:08.944008+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise
2019-10-01T09:14:08.944010+00:00 app[web.1]: raise value
2019-10-01T09:14:08.944013+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.6/site-packages/flask/app.py", line 1949, in full_dispatch_request
2019-10-01T09:14:08.944015+00:00 app[web.1]: rv = self.dispatch_request()
2019-10-01T09:14:08.944017+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.6/site-packages/flask/app.py", line 1935, in dispatch_request
2019-10-01T09:14:08.944019+00:00 app[web.1]: return self.view_functions[rule.endpoint](**req.view_args)
2019-10-01T09:14:08.944021+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.6/site-packages/dash/dash.py", line 146, in class_decorator
2019-10-01T09:14:08.944023+00:00 app[web.1]: **kwargs
2019-10-01T09:14:08.944026+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.6/site-packages/dash/authentication.py", line 61, in create_requires_auth
2019-10-01T09:14:08.944028+00:00 app[web.1]: return f(*args, **kwargs)
2019-10-01T09:14:08.944030+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.6/site-packages/dash/dash.py", line 598, in dispatch
2019-10-01T09:14:08.944033+00:00 app[web.1]: return self.callback_map[target_id]['callback'](*args)
2019-10-01T09:14:08.944034+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.6/site-packages/dash/dash.py", line 551, in add_context
2019-10-01T09:14:08.944037+00:00 app[web.1]: output_value = func(*args, **kwargs)
2019-10-01T09:14:08.944038+00:00 app[web.1]: File "/app/app.py", line 176, in update_hist
2019-10-01T09:14:08.944041+00:00 app[web.1]: mode='lines+markers', line=dict(color='blue')))
2019-10-01T09:14:08.944050+00:00 app[web.1]: TypeError: 'NoneType' object is not callable
What could be the problem, I will appreciate your help.