Solve 404 WordpPress pagination problems

If the number of posts in the admin panel is more than $query->set(‘posts_per_page’, ‘number of posts’);, in the place of output of posts 404 error may appear

Paste the code into your function.php file and don’t forget to change the number of entries in line $query->set(‘posts_per_page’, 3);

<?php 

function posts_per_page($query) {
    if(!is_admin()) {
        if(is_post_type_archive('post')) {
            $query->set('posts_per_page', 3);
         }
}
}

add_action('pre_get_posts', 'posts_per_page');

 ?>