Problem with paging on Multisite

If you’re using the category archive template you do not need to create a new WP_Query instance. Just filter the main query using pre_get_posts().

Put this in functions php or a plugin:

add_action( 'pre_get_posts', wp_se_pre_get_posts' );
function wp_se_pre_get_posts( $query ) {
    if ( is_admin() || ! $query->is_main_query || ! is_category( 'pressmeddelande' )
        return $query;

    $query->set( 'posts_per_page', 6 );

}