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Pass Paged into parameter array of query_posts

You should set get_query_var( 'paged' ); if you want your query to work with pagination.

$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
$args_news= array(
        'cat' => 1,
        'posts_per_page' => 2,
        'orderby' => 'post_date',
        'order' => 'DESC',
        'numberposts' => -1,
        'paged' => $paged,
    );

    query_posts( $args_news );
if ( have_posts() ) :
        while ( have_posts() ) :
            the_post();

          the_title();
          the_content();

          endwhile;
    endif;

for more information:https://codex.wordpress.org/Pagination