title: PermissionError: [Errno 13] Permission denied Flask.run()
body: <p>I am running MacOS X with python 3. The folder and files have 755 but I have also tested it in 777 with no luck. My question is if I have the right permissions why does it not let me run without sudo. Or are my settings incorrect?</p>
  
  <pre><code>cris-mbp:ProjectFolder cris$ python3 zbo.py 
  Traceback (most recent call last):
    File "zbo.py", line 9, in &lt;module&gt;
      app.run(host="127.0.0.1",port=81,debug=True)
    File "/usr/local/lib/python3.5/site-packages/flask/app.py", line 843, in run
      run_simple(host, port, self, **options)
    File "/usr/local/lib/python3.5/site-packages/werkzeug/serving.py", line 677, in run_simple
      s.bind((hostname, port))
  PermissionError: [Errno 13] Permission denied
  cris-mbp:ProjectFolder cris$ sudo python3 zbo.py 
   * Running on http://127.0.0.1:81/ (Press CTRL+C to quit)
   * Restarting with stat
   * Debugger is active!
   * Debugger pin code: 106-133-233
  </code></pre>