Error with displaying posts within a custom taxonomy

Hi,

My custom post type is named “tutorijal” and my custom taxnomy “serija”. I want to display only the tutorials (tutorijal) from the current serie (serija), so for example if the user is on the website-name/tutorials/xhtml-and-css, only to display posts belonging to category xhtml-and-css.

here’s my code from my taxonomy-serija.php :

<?php get_header(); ?>
    <div class="container">
      <div class="row">
        <div class="col-md-12">
			<?php
			$post_type = 'tutorijal';
			$tax = $wp_query->get_queried_object();
			$tax_terms = get_terms($tax);
			if ($tax_terms)
			{
				foreach ($tax_terms  as $tax_term)
				{
					$args=array(
				    'post_type' => $post_type,
					"$tax" => $tax->slug,
					'post_status' => 'publish',
					'posts_per_page' => -1,
					'ignore_sticky_posts'=> 1
								);
				$my_query = null;
				$my_query = new WP_Query($args);
				if( $my_query->have_posts() )
				{
					echo '<ol>';
					while ($my_query->have_posts()) : $my_query->the_post(); ?>
					<li><a href="<?php the_permalink() ?>" rel="bookmark" title="<?php the_title_attribute(); ?>"><?php the_title(); ?></a></li>
				<?php
				endwhile;
				echo '</ol>';
				}
				wp_reset_query();
				}
			}
			?>
        </div>
      </div>
<?php get_footer(); ?>

I var_dumped the $tax_terms and it gives me an error that goes like this : object(WP_Error)#304 (2) { [“errors”:”WP_Error”:private]=> array(1) { [“invalid_taxonomy”]=> array(1) { [0]=> string(16) “Invalid taxonomy” } } [“error_data”:”WP_Error”:private]=> array(o) { } }

Any help?

Thanks!