Hi dieudonne,
At the moment, the News2 does not use the page navigation of WordPress and the WP Pagenavi can not override the navigation of the theme.
In this case, you need to use the following shortcode of the plugin:
<?php wp_pagenavi(); ?>
Then fin the following code in the News2 theme to replace.
<?php gk_content_nav(); ?>
So, If you want to override the archive page, you can open the archive.php or category.php file to replace the gk_content_nav with wp_pagenavi.
With your site, I have helped you customize the category.php file in your child theme. Please check your site and the file to understand the issue.
Hope this helps!
