User-47214744 posted
What I've seen in other sites running into the same situation is that the validator expects a Referer for it to respond OK, which is why you see that it works when you use a browser since the browsers actually send that header, whereas Search Engines/Bots
never send that header.
If you see the status code you will notice that it is getting rejected and the code and content they return.
My recommendation to everyone using that is to add an attribute to the link rel="nofollow" so that neither SEO or bots actually follow that link which does not provide any value for search engines.
