title: python-telegram-bot.I already PORT 8443 but Error while bootstrap set webhook: Bad webhook: webhook can be set up only on ports 80, 88, 443 or 8443
body: <p>I just find the post without any reply on stackoverflow when i create this post...
  <a href="https://stackoverflow.com/questions/45533321/telegrambot-webhook-can-be-set-up-only-on-ports-80-88-443-or-8443-error-on">TelegramBot. &quot;Webhook can be set up only on ports 80, 88, 443 or 8443&quot; error on heroku webserver</a></p>
  <p>my testing code is here:</p>
  <pre><code>from configparser import ConfigParser
  import logging
  
  import os
      
  import telegram
  from flask import Flask, request
  from telegram.ext import  Updater, Dispatcher, MessageHandler, Filters, CommandHandler
  
  env = ConfigParser()
  env.read('config.ini')
  TOKEN = env['TELEGRAM']['ACCESS_TOKEN']
  
  PORT = int(os.environ.get('PORT', '8443'))
  
  updater = Updater(token=TOKEN)
  
  
  #
  #body part ( that's not important to show)
  #
  
  
  updater.start_webhook(listen=&quot;0.0.0.0&quot;,
                        port=PORT,
                        url_path=TOKEN)
  updater.bot.set_webhook(&quot;https://tgbot00.herokuapp.com/&quot; + TOKEN)
  updater.idle()
  </code></pre>
  <p>but server told me ...</p>
  <pre><code>here2021-03-19T14:48:06.712894+00:00 app[web.1]: Error while bootstrap set webhook: Bad webhook: webhook can be set up only on ports 80, 88, 443 or 8443
  
  2021-03-19T14:48:06.713033+00:00 app[web.1]: Failed bootstrap phase after 0 retries (Bad webhook: webhook can be set up only on ports 80, 88, 443 or 8443)
  </code></pre>
  <p>I have struggled these about a week and almost success
  but somehow so less information found on google</p>
  <p>Do I need to setup something on my remoted Linux system about PORT.?</p>
  <p>could someone help .?</p>
  <p>thx a lot...!</p>
  <p>UPDATE----------------------------------------
  <a href="https://github.com/python-telegram-bot/python-telegram-bot/wiki/Webhooks#heroku" rel="noreferrer">https://github.com/python-telegram-bot/python-telegram-bot/wiki/Webhooks#heroku</a></p>
  <p>I think this is not about SSL problem</p>
  <pre><code>Heroku
  On Heroku using webhook can be beneficial on the free-plan because it will
  automatically manage the downtime required. The reverse proxy is set up for you and an environment 
  is created. From this environment you will have to extract the port the bot is supposed to listen on. 
  Heroku manages the SSL on the proxy side, so you don't have provide the certificate yourself.
  </code></pre>