Pagination code don’t work

Hello,

I’m having some issues adding a pagination on a specific page.
Can someone help me?

I want to use this plugin to insert pagination with the following code:
<?php wp_pagenavi(); ?>

When I add this code, the pagination doesn’t appear.

The only pagination code I can make to work:

<?php
next_posts_link( 'Older Entries', $loop->max_num_pages );
previous_posts_link( ' - Newer Entries' );
?>

But it’s very ugly and I need to replace with the above one.

What could be?

My code: https://paste2.org/CpmZDs8x

Thanks in advance!