Google rich snippet - Missing required field "entry-title"

Question

I was trying to see if the microdata was configured well on my website, using the google structured data testing tool and it gives some errors. In this question, I'm asking about the first: Missing required field "entry-title".

I already enclosed the title of the post in entry-title class but it is not working. It is the code of my page that regards the error:

 <header itemscope itemtype="http://schema.org/Article">
    <figure>
       <img width="674" height="250" src="http://www.primapaginaonline.it/wp-content/uploads/2014/07/tagliodiverso-674x250.jpeg?3ef148" class="attachment-topimage wp-post-image" alt="tagliodiverso" itemprop="thumbnailUrl" /></figure>
    </figure>
<div itemprop="articleSection" class="single-page-category">Cultura</div>
<h1 itemprop="headline" class="entry-title single-entry-title"> Tagliodiverso, gli appuntamenti della Pietraia dei Poeti</h1>   
<div itemprop="description" class="meta-description">Con Tagliodiverso il museo a cielo aperto Pietraia dei Poeti stila un cartellone di incontri culturali incentrati sulla disabilità e l'accessibilità.</div>
    <div class="single-post-meta"></div>
</header>

Answer 1

Solved, I must enclose all the article in a <div class="hentry"> tag and all works!