When I use _e like in
<?php _e( 'Categories', 'theme'); ?>
the text form the nl.mo language file is used. But when I have
<?php printf(__ ( 'by %s', 'theme'), get_the_author()); ?>
It is not working and then I need to translate directly inside the theme file. Why is that?
PS I did translate the .po completely and the .mo is on the server and works..