Google Testing Tool hATOM Error

Can someone help me out with this? I’m lost… Very much appreciated.

I am getting this error:
Node is empty. Double check that this is desired an consider removing.

Here is the coding error I think:

com/contact/">About Me</a></li>
</ul></div>		</div><!-- .inside-navigation -->
	</nav><!-- #site-navigation -->

	<strong><div id="page" class="hfeed site grid-container container grid-parent"></strong>
		<div id="content" class="site-content">
			//mod content
function hatom_mod_post_content ($content) {
  if ( in_the_loop() && !is_page() ) {
    $content = '<span class="entry-content">'.$content.'</span>';