title: Python Webapp on Linux App Service Plan failed to start | future = tasks.async(future, loop=self)
body: <p>I have Python WebApp running on Linux App Service Plan.</p>
  <p>Im using following python code</p>
  <pre><code>import abc
  from datetime import datetime
  from types import CodeType
  from typing import ValuesView
  from flask import Flask, request
  from fyers_api import accessToken
  from fyers_api import fyersModel
  from azure.data.tables import TableServiceClient
  from azure.data.tables import TableClient
  import requests, json, urllib.parse
  from datetime import date
  
  
  app = Flask(__name__)
  
  # default route
  @app.route('/')
  def index():
      return 'Hello World!'
  
  </code></pre>
  <p>It was working fine till last week. I did modify code and after that deployed.
  It stopped working with below error.</p>
  <p>The strange part is that I have reverted the code to Original one. So practically there is no code change. The code runs on my Laptop without any issue. When I port it on Azure Linux Web App, it gives this error.</p>
  <p>2021-05-14T05:50:29.559Z INFO - Initiating warmup request to container rockettokensaverapp_0_0408fcd1 for site rockettokensaverapp
  2021-05-14T05:50:44.773Z INFO - Container rockettokensaverapp_0_0408fcd1 for site rockettokensaverapp initialized successfully and is ready to serve requests.
  2021-05-14T07:28:03.725Z INFO - Starting container for site
  2021-05-14T07:28:03.764Z INFO - docker run -d -p 9624:8000 --name rockettokensaverapp_1_ddb77933 -e WEBSITE_SITE_NAME=RocketTokenSaverApp -e WEBSITE_AUTH_ENABLED=False -e WEBSITE_ROLE_INSTANCE_ID=0 -e WEBSITE_HOSTNAME=rockettokensaverapp.azurewebsites.net -e WEBSITE_INSTANCE_ID=50a285a49ae3758d44951d408c7ec6cb3077821b90868ed2bf52d6c32be391fa -e HTTP_LOGGING_ENABLED=1 appsvc/python:3.8_20210226.3
  2021-05-14T07:28:11.002Z INFO - Initiating warmup request to container rockettokensaverapp_1_ddb77933 for site rockettokensaverapp
  2021-05-14T07:28:27.656Z ERROR - Container rockettokensaverapp_1_ddb77933 for site rockettokensaverapp has exited, failing site start
  2021-05-14T07:28:27.673Z ERROR - Container rockettokensaverapp_1_ddb77933 didn't respond to HTTP pings on port: 8000, failing site start. See container logs for debugging.
  /home/LogFiles/2021_05_15_lw1sdlwk00003C_default_docker.log (<a href="https://rockettokensaverapp.scm.azurewebsites.net/api/vfs/LogFiles/2021_05_15_lw1sdlwk00003C_default_docker.log" rel="nofollow noreferrer">https://rockettokensaverapp.scm.azurewebsites.net/api/vfs/LogFiles/2021_05_15_lw1sdlwk00003C_default_docker.log</a>)
  2021-05-15T17:17:39.915599409Z File &quot;/tmp/8d916ea417c6219/antenv/lib/python3.8/site-packages/asyncio/init.py&quot;, line 21, in 
  2021-05-15T17:17:39.915603209Z from .base_events import *
  2021-05-15T17:17:39.915606709Z File &quot;/tmp/8d916ea417c6219/antenv/lib/python3.8/site-packages/asyncio/base_events.py&quot;, line 296
  2021-05-15T17:17:39.915610509Z future = tasks.async(future, loop=self)
  2021-05-15T17:17:39.915614109Z ^
  2021-05-15T17:17:39.915617609Z SyntaxError: invalid syntax
  2021-05-15T17:17:39.923617989Z [2021-05-15 17:17:39 +0000] [38] [INFO] Worker exiting (pid: 38)
  2021-05-15T17:17:40.085196098Z [2021-05-15 17:17:40 +0000] [36] [INFO] Shutting down: Master
  2021-05-15T17:17:40.094651292Z [2021-05-15 17:17:40 +0000] [36] [INFO] Reason: Worker failed to boot.
  /home/LogFiles/2021_05_15_lw1sdlwk00003C_docker.log (<a href="https://rockettokensaverapp.scm.azurewebsites.net/api/vfs/LogFiles/2021_05_15_lw1sdlwk00003C_docker.log" rel="nofollow noreferrer">https://rockettokensaverapp.scm.azurewebsites.net/api/vfs/LogFiles/2021_05_15_lw1sdlwk00003C_docker.log</a>)
  2021-05-15T07:44:02.784Z ERROR - Container rockettokensaverapp_0_2f5e934c for site rockettokensaverapp has exited, failing site start
  2021-05-15T07:44:02.786Z ERROR - Container rockettokensaverapp_0_2f5e934c didn't respond to HTTP pings on port: 8000, failing site start. See container logs for debugging.
  2021-05-15T07:44:02.805Z INFO - Stopping site rockettokensaverapp because it failed during startup.
  2021-05-15T17:17:24.298Z INFO - Starting container for site
  2021-05-15T17:17:24.299Z INFO - docker run -d -p 4875:8000 --name rockettokensaverapp_0_0ba816d7 -e WEBSITE_SITE_NAME=RocketTokenSaverApp -e WEBSITE_AUTH_ENABLED=False -e WEBSITE_ROLE_INSTANCE_ID=0 -e WEBSITE_HOSTNAME=rockettokensaverapp.azurewebsites.net -e WEBSITE_INSTANCE_ID=d4e6216930e8a31ff922c40a616e74d0f121e0e471dd7869291ba087f2c488ec -e HTTP_LOGGING_ENABLED=1 appsvc/python:3.8_20210226.3
  2021-05-15T17:17:27.144Z INFO - Initiating warmup request to container rockettokensaverapp_0_0ba816d7 for site rockettokensaverapp
  2021-05-15T17:17:42.130Z ERROR - Container rockettokensaverapp_0_0ba816d7 for site rockettokensaverapp has exited, failing site start
  2021-05-15T17:17:42.147Z ERROR - Container rockettokensaverapp_0_0ba816d7 didn't respond to HTTP pings on port: 8000, failing site start. See container logs for debugging.
  2021-05-15T17:17:42.159Z INFO - Stopping site rockettokensaverapp because it failed during startup.
  /home/LogFiles/webssh/pm2.log (<a href="https://rockettokensaverapp.scm.azurewebsites.net/api/vfs/LogFiles/webssh/pm2.log" rel="nofollow noreferrer">https://rockettokensaverapp.scm.azurewebsites.net/api/vfs/LogFiles/webssh/pm2.log</a>)</p>