title: 404s in Umbraco - only works for directories and ASPX extensions
body: <p>I have an Umbraco 7 site with 404 errors configured and generally working fine as long as the URL ends in a directory name or has a .aspx file extension.</p>
  
  <p>Any other URLs for files that don't exist return a 404 HTTP status but the returned page is blank. How can I configure Umbraco to return my configured 404 page for all 404 responses?</p>
  
  <p>The site is currently configured with a node ID in the <code>error404</code> node in <code>umbracoSettings.config</code> and, as I say, works fine in specific cases. </p>
  
  <p>I've hunted around the web but not found much help. I tried implementing my own 404 handler by implementing the <code>INotFoundHandler</code> interface but the effect was the same. I've also tried adding the following to the <code>system.webserver</code> section of <code>web.config</code> but this doesn't seem to change anything, and in any case I want the 404 page to be editable in Umbraco ideally.</p>
  
  <pre><code>&lt;httpErrors existingResponse="PassThrough"&gt;
      &lt;remove statusCode="404" subStatusCode="-1" /&gt;
      &lt;error statusCode="404" path="~/404.aspx" responseMode="ExecuteURL" /&gt;
  &lt;/httpErrors&gt;
  </code></pre>
  
  <p>Advice very appreciated. </p>