next post link in same category

Hi,

Regarding https://codex.www.ads-software.com/Next_and_Previous_Links the following code should display post in same categories if post are registered in more than one category.

Unfortunatly it does not work

Any help would be appreciated.

<?php previous_post_link( '%link', _x( '<span class="meta-nav">&larr;</span>', 'Previous post link', 'spotlight' ), TRUE, ' ', 'category' ); ?>
<?php next_post_link('%link', _x( '<span class="meta-nav">&rarr;</span>', 'Next post link',     'spotlight' ), TRUE, ' ', 'category' ); ?>