title: flask only loading one webpage of the website and other webpages are getting NOTFOUND error
body: <p><a href="https://i.stack.imgur.com/ftSux.png" rel="nofollow noreferrer">Flask code</a></p>
  <p><a href="https://i.stack.imgur.com/43SPL.png" rel="nofollow noreferrer">the other webpage which is not loading</a></p>
  <p><a href="https://i.stack.imgur.com/GPGI1.png" rel="nofollow noreferrer">the webpage opened with FLASK</a></p>