W3C XHTML validation doesn't work

[Nikita]

Scenario:
Click on the "W3C" button (XHTML Validator).

Result:

The following error:

Status: 403 ForbiddenVary: RefererContent-type: text/html

 Markup Validation Service

Check the markup (HTML, XHTML) of Web documents

Sorry! This document can not be checked.

No User-Agent header found!

Please identify your software properly by providing the HTTP User-Agent string. Default from an underlying library (eg Java, Ruby, Coda, libwww) is not sufficiently unique in identifying your software. A good practice is to include a URI to more information about your service or software.

 The W3C Validator Team

Note:
You can check it also in the demo Rad Editor:
http://demos.telerik.com/aspnet-ajax/editor/examples/overview/defaultcs.aspx

It looks like the request format has been changed on the http://validator.w3.org/ side.

Could you please help me to resolve this problem? 

Thank you in advance.

[Rumen]

Hello,

Thank you for reporting this issue.

We are aware of it, it is logged with top priority and we are currently working on it.

Best regards,
Rumen
the Telerik team

[Ivan]

Hi,

a solution for this problem?

[Rumen]

Hello,

The problem is fixed and it should be available in the Latest Internal Build. It will not exist in the upcoming Q1 2013 SP1 release.

Regards,
Rumen
the Telerik team