title: Flask - 404 Not found : The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again
body: <p>I'm completely new to Flask. As a beginner I'm trying to print 'Hello World' on a web page. When run this Flask application, the browser throwing me a <code>404</code> error. It says <code>The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.</code></p>
  <p>Here is my <code>__init__.py</code> :</p>
  <pre><code>from flask import Flask
  
  app = Flask(__name__)
  
  from app import app
  </code></pre>
  <p>My <code>routes.py</code> file:</p>
  <pre><code>from app import app
  
  @app.route('/')
  @app.route('/index')
  def index():
      return &quot;Hello, World!&quot;
  </code></pre>
  <p>And my <code>microApp.py</code> file:</p>
  <p><code>from app import app</code></p>
  <p>Here is my working directory:</p>
  <pre><code>My Project/
    venv/
    app/
      __init__.py
      routes.py
    microApp.py
  </code></pre>
  <p>I set <code>FLASK_APP = microApp.py</code> and tried to run Flask. But the browser is throwing me an error.</p>
  <p>Please anyone help me, I'm a noob. Thanks in advance.</p>