Referenced AMP URL is not an AMP

@ahmedkaludi no i haven’t done any kind of redirection 301 on these pages but i want to tell you one more thing that those post redirecting to non-amp version are child post like:
Parent Post: https://www.vpnranks.com/reviews/vyprvpn/
Child Post: https://www.vpnranks.com/reviews/vyprvpn/kodi/
Parent post AMP version working fine but child post amp redirecting to non-amp i am sending you code which i use to create this custom posts hierarchy.

add_action('registered_post_type', 'make_posts_hierarchical', 10, 2 );

// Runs after each post type is registered
function make_posts_hierarchical($post_type, $pto){

    // Return, if not post type posts
    if ($post_type != 'post') return;

    // access $wp_post_types global variable
    global $wp_post_types;

    // Set post type "post" to be hierarchical
    $wp_post_types['post']->hierarchical = 1;

    // Add page attributes to post backend
    // This adds the box to set up parent and menu order on edit posts.
    add_post_type_support( 'post', 'page-attributes' );

}

/**
 * Get parent post slug
 *
 * Helpful function to get the post name of a posts parent
 */
function get_parent_post_slug($post) {
    if (!is_object($post) || !$post->post_parent) {
        return false;
    }

    return get_post($post->post_parent)->post_name;
}

/**
 *
 * Edit View of Permalink
 *
 * This affects editing permalinks, and $permalink is an array [template, replacement]
 * where replacement is the post_name and template has %postname% in it.
 *
 **/
add_filter('get_sample_permalink', function($permalink, $post_id, $title, $name, $post) {
    if ($post->post_type != 'post' || !$post->post_parent) {
        return $permalink;
    }

    // Deconstruct the permalink parts
    $template_permalink = current($permalink);
    $replacement_permalink = next($permalink);

    // Find string
    if(!is_amp_endpoint()) {
        $postname_string = '/%postname%/';
    }else{
        $postname_string = '/%postname%/amp/';
    }

    // Get parent post
    $parent_slug = get_parent_post_slug($post);

    $altered_template_with_parent_slug = '/' . $parent_slug . $postname_string;
    $new_template = str_replace($postname_string, $altered_template_with_parent_slug, $template_permalink);

    $new_permalink = [$new_template, $replacement_permalink];

    return $new_permalink;
}, 99, 5);

/**
 * Alter the link to the post
 *
 * This affects get_permalink, the_permalink etc.
 * This will be the target of the edit permalink link too.
 *
 * Note: only fires on "post" post types.
 */
add_filter('post_link', function($post_link, $post, $leavename){

    if ($post->post_type != 'post' || !$post->post_parent) {
        return $post_link;
    }

    $parent_slug = get_parent_post_slug($post);
    $new_post_link = str_replace($post->post_name, $parent_slug . '/' . $post->post_name, $post_link);

    return $new_post_link;
}, 99, 3);

/**
 * Before getting posts
 *
 * Has to do with routing... adjusts the main query settings
 *
 */
add_action('pre_get_posts', function($query){
    global $wpdb, $wp_query;

    $original_query = $query;
    $uri = $_SERVER['REQUEST_URI'];

    // Do not do this post check all the time
    if ( $query->is_main_query() && !is_admin()) {

        // get the post_name
        $basename = basename($uri);
        // find out if we have a post that matches this post_name
        $test_query = sprintf("select * from $wpdb->posts where post_type = '%s' and post_name = '%s';", 'post', $basename);
        $result = $wpdb->get_results($test_query);

        // if no match, return default query, or if there's no parent post, this is not necessary
        if (!($post = current($result)) || !$post->post_parent) {
            return $original_query;
        }

        // get the parent slug
        $parent_slug = get_parent_post_slug($post);
        // concat the parent slug with the post_name to get most of the url
        $hierarchal_slug = $parent_slug . '/' . $post->post_name;

        // if the concat of parent-slug/post-name is not in the uri, this is not the right post.
        if (!stristr($uri, $hierarchal_slug)) {
            return $original_query;
        }

        // pretty high confidence that we need to override the query.
        $query->query_vars['post_type'] = ['post'];
        $query->is_home     = false;
        $query->is_page     = true;
        $query->is_single   = true;
        $query->queried_object_id = $post->ID;
        $query->set('page_id', $post->ID);

        return $query;
    }

}, 1);