I have a web page that returns in W3C Validator as fully validated (and is green).
But when I run a check of the same URL in many SEO testing websites, it fails and tells me the errors it failed on:
a: The string
v:urlis not a registered keyword.
The relative code this is referring to is schema markup for the breadcrumbs:
<div id="breadcrumbs"> <span prefix="v: http://rdf.data-vocabulary.org/#"> <span typeof="v:Breadcrumb"><a href="http://www.bellavou.co.uk" rel="v:url" property="v:title"><span class="fa fa-home"><span class="breadcrumb_first">Home</span></span></a></span> <span class="fa fa-angle-right"></span> <span typeof="v:Breadcrumb"><a href="http://www.bellavou.co.uk/contact-us/" rel="v:url" property="v:title">Contact Us</a></span> </span> </div>
It’s also worth noting that the markup completely validates in Google’s Structured Data Testing Tool.
Why is it not validating in the third-party website checks, but more importantly, why is it showing as valid in the actual W3C website?