Query posts inside custom post type

have you set ‘paged’ => $paged at query_posts arguments?

source: https://codex.www.ads-software.com/Pagination

hi you can use this code
please put this code instead of this code

<?php if ( have_posts() ) : ?>

<!-- Add the pagination functions here. -->

<!-- Start of the main loop. -->
<?php while ( have_posts() ) : the_post();  ?>

<!-- the rest of your theme's main loop -->

<?php endwhile; ?>
<!-- End of the main loop -->

<!-- Add the pagination functions here. -->

<div class="nav-previous alignleft"><?php next_posts_link( 'Older posts' ); ?></div>
<div class="nav-next alignright"><?php previous_posts_link( 'Newer posts' ); ?></div>

<?php else : ?>
<p><?php _e('Sorry, no posts matched your criteria.'); ?></p>
<?php endif; ?>

Replace with

<div class="pagin"><span class="paginat">
			<?php
			$big = 999999999;
			echo paginate_links( array(
				'base' => str_replace( $big, '%#%', esc_url( get_pagenum_link( $big ) ) ),
				'format' => '?paged=%#%',
				'current' => max( 1, get_query_var('paged') ),
				'total' => $wp_query->max_num_pages,
				'show_all'     => False,
				'end_size'     => 1,
				'mid_size'     => 5,
				'prev_next'    => True,
				'prev_text'    => __('PREV'),
				'next_text'    => __('NEXT'),
				'type'         => 'plain',
				'add_args'     => False,
				'add_fragment' => ''
				)  );
			?>
			</span></div>

For single post pagination (with the <!–nextpage–> quicktag) urls look similar to this (without “/page”):
/ocalhost/product/testproduct/2/

https://codex.www.ads-software.com/Function_Reference/wp_link_pages

Or use previous_post_link() and next_post_link() to navigate to the next and previous post.
https://codex.www.ads-software.com/Function_Reference/previous_post_link
https://codex.www.ads-software.com/Function_Reference/next_post_link

Hello!
Thank you very much for all your answers. Unfortunately i was not yet able to solve the issue.

@lidya1859: yes, i use the ‘paged’ => $paged in my WP_Query query.

@piyush: Thank you for your code. When i replace the required parts, i see a nice counter from 1 to 5 pages with a “next” link, but when i click on any links, nothing happens. The page just reloads. I guess this is because the links are adding the /page/[pagenumber] to the url which is not working

@keesiemeijer: When i add the page number to the ULR without /page/, then it is leaving the URL with the page number but this does not effect the WP_Query.

Edit: I was able to create a pagination! I’ve modified Piyush code so it looks like this:

echo paginate_links( array(
				'base' => $permalink.'/%#%',
				'format' => '?page=%#%',
				'current' => max( 1, get_query_var('page') ),
				'total' => $wp_query2->max_num_pages,
				'show_all'     => False,
				'end_size'     => 1,
				'mid_size'     => 5,
				'prev_next'    => True,
				'prev_text'    => __('PREV'),
				'next_text'    => __('NEXT'),
				'type'         => 'plain',
				'add_args'     => FALSE,
				'add_fragment' => ''
				)  );

(The $permalink variable is the permalink of the single product)
And in my WP_Query i use ‘paged’ => get_query_var(‘page’)

Thank you very very much for your support!