title: asp.net webform keep keep being authenticated in an mvc application
body: <p>I have a well-running mvc4 application with Forms authentication. Then I need to do some report with ReportViewer, so I have to add a webform page with an ReportViewer inside and put in an iframe in an mvc Razor page.</p>
  
  <p>The problem is when I browse that webform (even directly or from the Controller.Action that return the Razor page with iframe embbeded), a basic anthentication form keeps being displayed and asked for a username/password.</p>
  
  <p>Even I have added this to web.config</p>
  
  <pre><code> &lt;location path="pathToWebForm.aspx"&gt;
     &lt;system.web&gt;
       &lt;authorization&gt;
         &lt;allow users="*"/&gt;
       &lt;/authorization&gt;
     &lt;/system.web&gt;
   &lt;/location&gt;
  </code></pre>
  
  <p>Please help on how to remove this basic authentication form from the webform.
  Thanks in advance.</p>
  
  <p>UPDATED: The authentication form ONLY appears if I put the webform inside a folder. Everything goes well if the webform is in root folder of application.</p>