After implementing metatags in on of my Drupal sites, I realized Metatags weren't rendering in the front page, but were in every other.
After searching the net I found this post:
The problem seems to occur only on sites that don't render any actual content on a page (blocs don't count).
The solution I aplied was simply to add
To The page.tpl.php of the current theme.
Hope it helps!