Custom post type pagination /page/2 is giving a 404

pagination works everywhere on my site but it isnt working in category.php. When i click page 2 it goes to… domain.com/category/cat-slug/page/2

by the way this is showing custom post types within certain categories (no actual plain ‘posts’)

But when the page loads its just the 404 page?

In permalinks I have /%postname%/ although I have set category base to ‘category’ just to be safe.

I also know this is kind of a convoluted way of doing it but i wasnt sure a better way.

<?php

get_header(); ?>

<div class="home-gradient">
<div id="container">
<div class="content-wrap">  

<?php 

    $uri = $_SERVER['REQUEST_URI'];
    $elms = explode('/', $uri);

    $categ = get_category_by_slug($elms[3]);
    $categ_id = $categ->term_id;

    if ( get_query_var('paged') ) {
    $paged = get_query_var('paged');
  } elseif ( get_query_var('page') ) {
    $paged = get_query_var('page');
  } else {
    $paged = 1;
  }

  $myquery = new WP_Query(array(
        'post_type' => 'any',
            'paged' => $paged,
            'posts_per_page' => 1,
      'cat' => $categ_id)
        );

        while ( $myquery->have_posts() ) : $myquery->the_post(); 

        $img_id = get_post_meta($post->ID,'main_image',true);
        $img_url = wp_get_attachment_url($img_id);

    ?>
blah blah code here for output

    <?php

  endwhile;
   wp_pagenavi( array( 'query' => $myquery ) );
   ?>