wp parse args – tag archive web page not discovered

I’m pretty new to wordpress…
I do not perceive the place I’m going unsuitable however I wish to create an archive web page of all of the tags I’ve utilized in a customized submit. Mainly I used the tags to separate the years 2014 2015 2016 and many others I wish to present all of the posts inside that tag with this sample:

<h1>2014</h1>
submit

<h1>2015</h1>
submit

I created tag-2015.php and it really works with out a downside after I go to create tag.php it offers me web page not discovered. My beginning code

<?php 
            // Resetto la question se necessario
            //wp_reset_postdata();
            
            /** 
             * Preparo gli argomenti
             *
             * Possibili parametri:
             * 'orderby'                => 'title',
             * 'order'                  => 'ASC',
             * 'posts_per_page'         => 3,
             * 'category_name'          => 'featured',
             * 'cat'                    => -1 //esclude una categoria o pi첫 categorie dalla question
             */ 
            $args = array(
                'post_type' => 'portfolio',
                'order'     => 'DIS',
            
            );
            
            // Eseguo la question 
            $the_query = new WP_Query($args); 
            
            // Conto gli elementi 
            $depend = $the_query->post_count;
            ?>

Thanks for the assistance
Andrea