title: Dash app auto update with dcc.Interval not working
body: <p>I am trying to get my dash dashboard to auto update using Dcc.Interval and Callbacks. I can't figure out what I am doing wrong here. The html.P component &quot;children&quot; are not updating and it doesn't seem like the Interval is bein initiated:</p>
  <pre><code>app.layout = html.Div([
  # Previous day column
  dbc.Col([html.H1(PREV_DAY,
                   style={'textAlign': 'center', 'height': '5%', 'margin-top': '30px', 'margin-bottom': '25px',
                          'font-family': 'Consolas', 'font-size': 'xxx-large'}),
           dbc.Card(
               [
                   dbc.CardBody(
                       [
                          html.H4(id='card_title_1', children=['Sales'], className='card-title'),
                          html.P(id='card_text_1', children=['Sample text.']),
                          dcc.Interval(
                               id='interval-component',
                               interval=10 * 1000,  # in milliseconds
                               n_intervals=0
                           )
                       ], style={'textAlign': 'center', 'font-family': 'Consolas'}
                   )
               ], style={'margin-top': '15px', 'margin-bottom': '15px', 'height': '30%'}
           ),
  </code></pre>
  <p>I am trying to update the html.P(id='card_text_1') element with each interval. Here is my callbacks:</p>
  <pre><code>### SECTION - Callbacks ###
  @app.callback(
      Output('card_text_1', 'children'),
      Input('interval-component', 'n_intervals'))
  
  def update_metrics(n):
      salesYest = 'test'
      return [{}.format(salesYest)]
  </code></pre>