posts_nav_link not working on category page

i have archive.php with this code

<?php get_header(); ?>

	<!-- - - - - - - - - - - - - - - Container - - - - - - - - - - - - - - - - -->	

	<section class="container sbr clearfix">

		<!-- - - - - - - - - - Page Header - - - - - - - - - - -->	

		<div class="page-header">

			<h1 class="page-title"> <?php single_cat_title(); ?> </h1>

		</div><!--/ .page-header-->

		<!-- - - - - - - - - end Page Header - - - - - - - - - -->	

		<!-- - - - - - - - - - - - - - - Content - - - - - - - - - - - - - - - - -->		

		<section id="content">

			<section class="content-event">

				<article class="event-item clearfix">
									             <?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>

					<div class="event-body">

						<?php // check if the post has a Post Thumbnail assigned to it.
if ( has_post_thumbnail() ) {
	the_post_thumbnail('medium');
} ?>

					</div><!--/ .event-body-->

					<div class="event-meta">
						<h3 class="title">
				<a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><?php the_title(); ?></a></h3>

						<table class="event-table">

							<tr>
								<td><strong>Model:</strong></td>
								<td><?php the_field('model'); ?></td>
							</tr>
							<tr>
								<td><strong>Pret:</strong></td>
								<td><?php the_field('pret'); ?> €</td>
							</tr>
                                                        <tr>
								<td><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title_attribute(); ?>"><img src="https://fcservizi.ro/wp-content/uploads/2013/03/detalii.jpg"></a></td>

							</tr>
						 </table><!--/ .event-table-->

					</div><!--/ .event-meta-->
					<?php endwhile; endif; ?>
				</article><!--/ .event-item-->

			</section><!--/ content-event-->

		</section><!--/ #content-->
 		<!-- - - - - - - - - - - - - - end Content - - - - - - - - - - - - - - - - -->
		<!-- - - - - - - - - - - - - - - Sidebar - - - - - - - - - - - - - - - - -->
<?php if ( !function_exists('dynamic_sidebar')
|| !dynamic_sidebar('sidebar') ) : ?>
<?php endif; ?>
			</section><!--/.container -->
	<?php get_footer(); ?>

and i can”t make the nav_link to show up, pls help