title: Strange IIS 403.14 Issue with MVC Based App
body: <p>We have an ASP.NET MVC 5 App currently running on IIS 10. Everything worked fine for months, however, suddenly 2 days back we started seeing a "403.14" error on random websites. </p>
  
  <pre><code>403 – Forbidden: Access is denied.
  You do not have permission to view this directory or page using the credentials that you supplied.
  </code></pre>
  
  <p>And what's even strange is that the error goes away if we toggle error page 403 setting in IIS (Show Detailed Error, Show Detailed Local, etc.) only to come back in some different website or even in the same website after a while.</p>
  
  <ol>
  <li>We have a single folder with the compiled MVC code with probably a dozen IIS sites (different domain names) mapped to the same folder.</li>
  <li>We have URLRewrite module installed.</li>
  <li><p>The CLR version is .NET 4.0.x </p></li>
  <li><p>We have tried restarting the IIS service (World Wide web Publishing service)</p></li>
  <li>Also, rebooted the server.</li>
  <li>Based on some suggestions, we added runAllManagedModulesForAllRequests to web.config webserver modules config.</li>
  <li>The Application pool has Run 32-bit applications enabled.</li>
  </ol>
  
  <p>What could be causing this? The error going away and coming back has confused us even more.</p>