title: ERR_ADDRESS_INVALID, 404 not found, localhost:8000
body: <p>I don't really know where to start and also don't really know where the issue comes from that's why I couldn't find a precise title for this question. Here is my problem.</p>
  
  <p>I copied this code from github, as part of a tutorial to learn about API's : </p>
  
  <pre><code>from flask import Flask
  app = Flask(__name__)
  
  
  @app.route('/readHello')
  def getRequestHello():
      return "Hi, I got your GET Request!"
  
  @app.route('/createHello', methods = ['POST'])
  def postRequestHello():
      return "I see you sent a POST message :-)"
  
  
  @app.route('/updateHello', methods = ['PUT'])
  def updateRequestHello():
      return "Sending Hello on an PUT request!"
  
  
  @app.route('/deleteHello', methods = ['DELETE'])
  def deleteRequestHello():
      return "Deleting your hard drive.....haha just kidding! I received a DELETE request!"
  
  if __name__ == '__main__':
      app.debug = True
      app.run(host='0.0.0.0', port=8000)
  </code></pre>
  
  <p>I installed a virtual machine with vagrant and it runs perfectly. When I try to run this code in the machine(I tried on my local machine and have the same issue), the terminal returns this : </p>
  
  <pre><code>vagrant@vagrant:/vagrant$ python api_server.py
   * Serving Flask app "api_server" (lazy loading)
   * Environment: production
     WARNING: This is a development server. Do not use it in a production deployment.
     Use a production WSGI server instead.
   * Debug mode: on
   * Running on http://0.0.0.0:8000/ (Press CTRL+C to quit)
   * Restarting with stat
   * Debugger is active!
   * Debugger PIN: 203-304-000
  </code></pre>
  
  <p>So I try to access the page on <a href="http://0.0.0.0:8000/" rel="nofollow noreferrer">http://0.0.0.0:8000/</a> but I get this error "ERR_ADDRESS_INVALID". When I try with <a href="http://127.0.0.1:8000" rel="nofollow noreferrer">http://127.0.0.1:8000</a> (not sure what the difference is but I found that it worked for some people) I get another error, this time 404 page not found. </p>
  
  <p>Thanks for the help.</p>