title: Dash Plotly error : Stuck on Loading... page after server run
body: <p>Could you please help me with this error.
  The page stuck with loading.... message but never loads.</p>
  
  <p>There's no error on server run.</p>
  
  <p>This is my code:</p>
  
  <pre><code>import dash
  import dash_core_components as dcc
  import dash_html_components as html
  import pandas as pd
  import plotly.graph_objects as go
  import numpy as np
  
  df1 = pd.read_csv('lines.csv', encoding='latin-1', low_memory=False)
  df1.rename(columns={"Order Type": "OrderType"}, inplace=True)
  
  df1.loc[(df1.Processed != '?'), 'OrderTypeProcessed'] = df1['Qty']
  df1.loc[(df1.Processed == '?'), 'OrderTypeProcessed'] = 0
  
  df2 = df1.groupby('OrderType').sum()
  df3 = df1.groupby(' Packout station Number').sum()
  df4 = df1.groupby('Packout station Operator').sum()
  df5 = df1.groupby('Product Category').sum()
  df1.rename(columns={df1.columns[12]:'Received Time'}, inplace=True)
  df6 = df1.groupby('Received Time').sum()
  df7 = df1.groupby('Cut Off Time').sum()
  
  
  
  
  df2.reset_index(inplace=True)
  df3.reset_index(inplace=True)
  df4.reset_index(inplace=True)
  df5.reset_index(inplace=True)
  df6.reset_index(inplace=True)
  df7.reset_index(inplace=True)
  
  df5['Product Category'] = df5['Product Category'].str.upper()
  
  app = dash.Dash()
  app.layout = html.Div([
      html.H1(children = "Dashboard Para Gestão De Produção - Caio",
      style = {'textAlign' : 'center',}),
          html.Div(children = "_______________________________",
                   style = {'textAlign' : 'center',}),
  
      dcc.Graph(
          id = 'lines-chart',
          figure = {
              'data' : [
          {'x': df2['OrderType'], 'y': df2['Qty'],                'type': 'bar', 'name': 'Dropado'},
          {'x': df2['OrderType'], 'y': df2['OrderTypeProcessed'], 'type': 'bar', 'name': 'Realizado'}
  
  
              ],
              'layout' : {
                  'title': 'Grafico'
              }
          }
      )
  
  ])
  
  
  if __name__ == '__main__':
      app.run_server(port =4050)
  </code></pre>
  
  <p>Could you please take a look, I tried call assets in app, however it also didn't work.</p>
  
  <p><a href="https://i.stack.imgur.com/ppyzG.png" rel="nofollow noreferrer">Here</a> is the page after server run.</p>