I checked my webpage on a html5 validator and I got 3 types of errors:
Error1: Attribute name not allowed on element link at this point.
From line 19, column 5; to line 19, column 56
!" />↩ <link name="twitter:url" href="http://localhost/" />↩
Error2: Element link is missing one or more of the following attributes: itemprop, property, rel.
From line 19, column 5; to line 19, column 56
!" />↩ <link name="twitter:url" href="http://localhost/" />
Error3: Element meta not allowed as child of element ul in this context. (Suppressing further errors from this subtree.)
From line 1506, column 19; to line 1506, column 72
<meta itemprop="itemListOrder" content="Descending" />↩