HTTP Error 403.14 – Forbidden – The Web server is configured to not list the contents of this directory

keep this into your web config file then rename the add value=”yourwebformname.aspx”

<system.webServer>
    <defaultDocument>
       <files>
          <add value="insertion.aspx" />
       </files>
    </defaultDocument>
    <directoryBrowse enabled="false" />
</system.webServer>

else

<system.webServer>
    <directoryBrowse enabled="true" />
</system.webServer>