Problems with pagination and custom post types

I’m trying to set up pagination for the categories of my Custom Post Type ‘listing’, I’m using the WP-Navi plugin.

Basically it works for the first page which is:
https://localhost/clients/win/category/listings/photographers

..but on the second page it shows as a 404 error:
https://localhost/clients/win/category/listings/photographers/page/2

For permalinks I’m using: /%postname%/%post_id%

Before I post some snippets of my code I just want to point out I’ve already read through the following topic that seems to have solved most peoples issues: https://www.ads-software.com/support/topic/pagination-with-custom-post-type-listing?replies=36.

<?php
$loop = custom_query_posts( array(
   'cat' => get_cat_ID(single_cat_title( '', false )),
   'post_type' => 'any',
   'posts_per_page' => 3,
   'meta_key' => 'user_type',
   'orderby' => 'meta_value title',
   'order' => 'ASC',
   'paged' => get_query_var('paged') ? get_query_var('paged') : 1
   )
);

while (have_posts()) : the_post();

   // Loop content

endwhile;

wp_pagenavi();
?>

I’m using @rafaelxy’s code from the above topic for the custom_query_posts(); but it doesn’t seem to have made much difference :/

Any ideas?