ImportError: cannot import name '_wsgi_encoding_dance' from 'werkzeug._internal'

[vedantmehta08]

When I try to run this basic dash code (copied directly from the dash plotly documentation), it gives out this error:
ImportError: cannot import name '_wsgi_encoding_dance' from 'werkzeug._internal'

from dash import Dash, html, dcc
import plotly.express as px
import pandas as pd

app = Dash(__name__)

df = pd.DataFrame({
    "Fruit": ["Apples", "Oranges", "Bananas", "Apples", "Oranges", "Bananas"],
    "Amount": [4, 1, 2, 2, 4, 5],
    "City": ["SF", "SF", "SF", "Montreal", "Montreal", "Montreal"]
    })

fig = px.bar(df, x="Fruit", y="Amount", color="City", barmode="group")


app.layout = html.Div(children=[
    html.H1(children='Hello Dash'),

    html.Div(children='''
        Dash: A web application framework for your data.
    '''),

    dcc.Graph(
        id='example-graph',
        figure=fig
        )
    ])


if __name__ == '__main__':
    app.run_server(debug=True)

Here's the full traceback of the importerror:

---------------------------------------------------------------------------
ImportError                               Traceback (most recent call last)
<ipython-input-46-a81edd5f2a5b> in <module>
     25 
     26 if __name__ == '__main__':
---> 27     app.run_server(debug=True)

~\AppData\Local\Continuum\anaconda3\lib\site-packages\dash\dash.py in run_server(self, port, debug, dev_tools_serve_dev_bundles, dev_tools_hot_reload, dev_tools_hot_reload_interval, dev_tools_hot_reload_watch_interval, dev_tools_hot_reload_max_retry, dev_tools_silence_routes_logging, **flask_run_options)
   1283                     )
   1284 
-> 1285                 return dict(
   1286                     user_callback_output=map_grouping(lambda x: no_update, output),
   1287                     interval_disabled=False,

~\AppData\Local\Continuum\anaconda3\lib\site-packages\flask\app.py in run(self, host, port, debug, load_dotenv, **options)
    938         cli.show_server_banner(self.env, self.debug, self.name, False)
    939 
--> 940         from werkzeug.serving import run_simple
    941 
    942         try:

~\AppData\Local\Continuum\anaconda3\lib\site-packages\werkzeug\serving.py in <module>
     28 
     29 from ._internal import _log
---> 30 from ._internal import _wsgi_encoding_dance
     31 from .exceptions import InternalServerError
     32 from .urls import uri_to_iri

ImportError: cannot import name '_wsgi_encoding_dance' from 'werkzeug._internal' (C:\Users\vmehta\AppData\Local\Continuum\anaconda3\lib\site-packages\werkzeug\_internal.py)

Environment:

• Python version: 3.7.1
• Werkzeug version: 2.1.1

I also tried running the above code after downgrading the werkzeug version to 2.0.3 but it throws the same error.

[tachyondecay]

I am unable to reproduce this in a fresh repl: https://replit.com/@tachyondecay/DifficultBlankBackslash

Likely a problem with your environment.

[vedantmehta08]

Thanks for looking into this. I am not able to understand the root cause either. Tried asking it on stack overflow as well. I checked the source code as well, but everything looks okay. Any idea how can I check environment compatibility?

[tachyondecay]

Unfortunately I'm not familiar with Anaconda. When I get errors like this, I destroy and recreate my virtual environment (installing all dependencies from scratch).