WebRequest authentication 401

Set location in web.config file to service url page. 

< location path="aspxpage.aspx">
< system.webServer>
        < security>
          < authentication>
            <anonymousauthentication enabled="true">
                  <windowsauthentication enabled="false">
                   </windowsauthentication>
            < /anonymousauthentication>
          </authentication>
        </security>
</system.webServer>

</location>