iFrame doesn't work in this case?
<p>I need a way to display some websites in an iframe.
But it doesn't work, why ?</p>

<pre><code>&lt;iframe src="https://www.msn.com/it-it/" &gt;&lt;/iframe&gt;
&lt;iframe src="http://www.lastampa.it/" &gt;&lt;/iframe&gt;
</code></pre>

<p>As you can see here, only the iframe on the right does work:</p>

<p><a href="http://codepen.io/anon/pen/EgGrjQ" rel="nofollow">http://codepen.io/anon/pen/EgGrjQ</a></p>