Plugins Problems with Custom Template Page

Hello to everyone,

I am running the WordPress Website “https://agamhealth.com/underdog/blog/” and I am trying to make the plugins working with the custom page template.

I’ve created a new file “blog.php” with the following code:

<?php
/*
Template Name: Blog Page
*/
?>

<?php get_header(); ?>

// my custom loop code loading all posts from category "blog"

<?php get_footer(); ?>

Header is added to the page, but don’t know why the plugins are not loaded for custom page.

Anyone knows the problem? Thank you!