from flask import Flask, render_template
import os


app = Flask(__name__)

@app.route('/')
def webprint():
    return(render_template('index.html'))

if __name__ == "__main__":
    app.run(host='0.0.0.0', port=5000)


from flask import Flask, render_template
import os


app = Flask(__name__)

@app.route('/')
def webprint():
    return(render_template('index.html'))

if __name__ == "__main__":
    port = int(os.environ.get('PORT', 5000))
    app.run(host='0.0.0.0', port=port)

Change default port