title: httpErrors ExecuteUrl not redirecting
body: <p>I have an asp.net hybrid web forms/mvc application.  I'm attempting to use the httpErrors tag in my web.config to redirect to a custom error page when a user attempts to upload a file that exceeds my maxAllowedContentLength.</p>
  
  <p>While the "Redirect" responseMode works fine, I cannot get the "ExecuteUrl" responseMode to work.  </p>
  
  <p>This problem occurs both when unit testing in Visual Studio 2013 using IIS Express, and when deployed to a machine running IIS 7.5.</p>
  
  <p>Using "Redirect" with the full path to an mvc controller works fine:</p>
  
  <pre><code>    &lt;httpErrors errorMode="Custom" existingResponse="Replace"&gt; 
    &lt;remove statusCode="404" subStatusCode="13" /&gt; 
    &lt;error statusCode="404" subStatusCode="13" prefixLanguageFilePath=""
       path="http://localhost:12345/Error/ErrorFileUploadSizeExceeded" responseMode="Redirect" /&gt; 
  &lt;/httpErrors&gt;
  </code></pre>
  
  <p>However, using "ExecuteUrl" with the relative path does not work (instead I see the default iis 404 page, obviously iis cannot find the relative path):</p>
  
  <pre><code>    &lt;httpErrors errorMode="Custom" existingResponse="Replace"&gt; 
    &lt;remove statusCode="404" subStatusCode="13" /&gt; 
    &lt;error statusCode="404" subStatusCode="13" prefixLanguageFilePath=""
       path="/Error/ErrorFileUploadSizeExceeded" responseMode="ExecuteURL" /&gt; 
  &lt;/httpErrors&gt;
  </code></pre>
  
  <p>What do I need to change to get "ExecuteURL" to work?</p>