It worked when I used a 3rd party plugin. But now I use this code in elements:
<div class="author-box">
<?php
global $post;
$author_id = $post->post_author;
?>
<div class="avatar"><?php echo get_avatar( get_the_author_meta( $author_id )); ?></div>
<h5 class="author-title"><?php printf( esc_attr__( 'About %s', 'the author' ), get_the_author_meta( 'display_name') );?></h5>
<div class="author-summary">
<p class="author-description"><?php echo wp_kses( get_the_author_meta( 'description' ), null ); ?></p>
<div class="author-links">
<a>" title="Read more">
...
</a>
</div>
</div>
</div>
Since then the gravatar wont show