a-tag doesn't work

Hi! My headline h2 consists an a-tag which links to the single.php – sadly it doesn’t work. Does anybody know why?

Url: dstruning.com

<li class="entry">
     <div class="post-head"><time>Mrz.17 2013</time><h2><a href="https://www.dstruning.com/blog/inspiration/samsara/" title="Samsara">Samsara</a></h2></div>
     <div class="post-thumb"><a href="https://www.dstruning.com/blog/inspiration/samsara/" title="Samsara"><img width="500" height="280" src="https://www.dstruning.com/wp-content/uploads/2013/03/samsara-500x280.png" class="attachment-post-thumbnail wp-post-image" alt="samsara" /></a></div>
     <div class="post-excerpt clearer">Samsara is a non-verbal guided meditation about the birth, death and rebirth. It's really sculptured, produced and directed by the power flow and the interconnectedness of things.</a></div>
</li>

Best, David