Dash using same port

app1.py

#!/usr/bin/env python

import dash
import dash_html_components as html
import dash_core_components as dcc

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

app.layout = html.Div([

        'Group outliers by: ',
        html.Div([
            dcc.Dropdown(
                id='group-by',
                options=[{'label': 1, 'value': 'hi'}, {'label': 2, 'value': 'hello'}],
                value='hello'
                ),
            ],
        ),
        'Sample HTML'

])

app.run_server(debug=False, port= 8050, host= 'localhost')