title: NextJS On-demand entries Returns 404
body: <p>I'm currently experiencing an issue with on-demand entries where when it requests a page to be compiled on the fly, it returns a 404 from the dev-server.</p>
  <p>Below is the typical pages directory structure. When inspecting dev_tools console, there is a fetch call to the dev server to compile the page, in this case article.tsx (/article/article-slug), the fetch request returns a 404.</p>
  <pre><code>.
  +-- pages
  |   +-- latest-news
  |       +-- index.tsx
  |   +-- article
  |       +-- [slug].tsx
  </code></pre>
  <p>Environment Details:</p>
  <ul>
  <li>OS: Ubuntu 18.04.4 LTS</li>
  <li>Node: v15.8.0</li>
  <li>NPM: 6.14.11</li>
  <li>NextJS: 10.0.5</li>
  </ul>