Pagination not working for cpt

I'm using this script to catch posts from a custom post type

$paged = ( get_query_var('paged') ) ? get_query_var('paged') : 1;
$args = array(
          'post_status' = array('publish', 'future'),
          'post_type' = 'evento',
          'orderby' = 'date',
          'order' = 'DESC',
          'posts_per_page' = 9,
          'paged' = $paged
     );

If I set Settings >> Reading >> Blog pages show at most to 6, site return 404 on the second page. If I set to 5, works fine. Why it happens?

I'm using roots theme.