title: flask.cli.NoAppException: Application crashing
body: <p>My Flask Application is crashing when I'm trying to access it.</p>
  
  <p>This is similar error to <a href="https://stackoverflow.com/questions/41474520/flask-flask-cli-noappexception-with-app-factory">this</a> or <a href="https://stackoverflow.com/questions/41403465/flask-app-will-not-load-app-py-the-file-path-provided-app-does-not-appear-to">this</a>. However, my set-up seems correct.</p>
  
  <blockquote>
    <p>flask.cli.NoAppException: The file/path provided (server) does not appear to exist.  Please verify the path is correct.  If app is not on PYTHONPATH, ensure the extension is .py</p>
  </blockquote>
  
  <p>My environment variable correctly set.</p>
  
  <pre><code>export FLASK_APP=server.py
  export FLASK_DEBUG=1
  </code></pre>
  
  <p>My server file is <code>server.py</code>, and I don't have any <code>__init__.py</code> in the directory.</p>
  
  <p>I don't recall having change anything special in the code. Where does the bug could come from?</p>