Currently I'm facing a really strange problem I can't seem to fix normally. 
I've using pagination on my category pages. I've got a 'News' category with some sub categories. One sub category is 'MVO nieuws'. 

When I visit '/mvo-nieuws' the pagination is working (showing an older posts link). 

    if ($paged) : ?>
		<nav class="page-nav archive">

			<?php if ($prev = get_previous_posts_link()) : ?>
				<div class="alignleft">
					<span class="fo icons-angle-circled-left"></span>
					<span><?php previous_posts_link( 'Nieuwe berichten' ); ?></span>
				</div>
			<?php endif;

			if ($next = next_posts($listPosts->max_num_pages, false)) : ?>
				<div class="alignright">
					<span>
						<a href="<?= $next; ?>">Oudere berichten</a>
					</span>
					<span class="fo icons-angle-circled-right"></span>
				</div>
			<?php endif; ?>

		</nav>
	<?php endif; ?>

The pagination is forwarding to `'/mvo-nieuws/page/2'`, but that page couldn't be found. I'll found out this is because its a subcategory of 'News', but I don't know why this seems to be a problem. 

I've removed the category as a subcategory and now it's working. All my other primary categories are also working fine, but the subcategories are facing this problem.

My permalink settings are: `'/%category%/%postname%/'`.
Hopefully anyone can help me out, thanks in forward!