Links within Wordpress excerpt don't work

Question

On our site we have a speakers page for courses. Main post has the bio and I have added a sidebar for each post to show picture and the excerpt. The excerpt only contains links to websites and their social media sites. The links in the excerpt don't seem to be clickable. http://www.socialmediaacademy.org.uk/index.php/course-speakers/ Is there a way to make them clickable? Here is the code for the sidebar:

<div id="sidebarbio">
<ul class="sidebar_list">

    <?php if (!function_exists('dynamic_sidebar') || !dynamic_sidebar()) : ?>
    <li class="widget">

    </li>

    <div class="post">
        <div>
            <?php // if there's a thumbnail
                if($thumb !== '') { ?>
                <p>
                    <img src="<?php echo $thumb; ?>"
                    class="<?php if($thumb_class !== '') { echo $thumb_class; } else { echo "left"; } ?>"
                    alt="<?php if($thumb_alt !== '') { echo $thumb_alt; } else { echo the_title(); } ?>"
                    />
                </p>
                <?php } // end if statement
                // if there's not a thumbnail
                else { echo ''; } ?>

                <?php the_excerpt();  ?>


            <?php $image = get_post_meta($post->ID, 'image', TRUE); ?>
            <?php if($image) { ?><img src="<?php echo $image; ?>" alt="Alt Text" /><?php } ?>
         </div>

    </div>

    <?php endif; ?>
</ul>

Answer 1

Figured it out - For that particular sidebar, I had set z-index=-1 in my style sheet. This disabled the links. Not sure why? Does anybody else know why?