Author archive pages loading slow

Besides the fact that these pages load slow no matter how many posts an author has written, these pages also get a http error, when i do a check (via https://httpstatus.io/).
Bear in mind that I am not a proper developer, and this project was once outsourced, so I am just trying to get this fixed.
I have read something about query_posts being deprecated, so this is where my focus went, but I wasn’t able to do anything.
Here’s the code, I appreciate the time.

<?php 
    // Register Calendar widget scripts
   function snaplap_widget_calendar_scripts_and_styles(){
    wp_register_style( 'LatoWidget', get_stylesheet_directory_uri() . '/js_calendar/css/Lato_300_400_700.css');
    wp_enqueue_style( 'Lato' );
    wp_register_style( 'FontAwasomeCalendarWidget', get_stylesheet_directory_uri() . '/js_calendar/css/fontawesome.css');
    wp_enqueue_style( 'FontAwasomeCalendarWidget' );
    wp_register_style( 'stylePersonalCalendarWidget', get_stylesheet_directory_uri() . '/js_calendar/css/style-personal.css');
    wp_enqueue_style( 'stylePersonalCalendarWidget' );

    // Register and Enqueue a Script
    // get_stylesheet_directory_uri will look up child theme location
    wp_register_script( 'jQueryLatestCalendarWidget', get_stylesheet_directory_uri() . '/js_calendar/js/jquery-latest.min.js');
    wp_enqueue_script( 'jQueryLatestCalendarWidget' );
    wp_register_script( 'simpleCalendarWidget', get_stylesheet_directory_uri() . '/js_calendar/js/simplecalendar.js');
    wp_enqueue_script( 'simpleCalendarWidget' );
}

add_action('wp_enqueue_scripts', 'snaplap_widget_calendar_scripts_and_styles'); 
?>

<?php get_header(); ?>

<div id="core" class="snap-left-working-area search-result">

	<div id="content">
            
				<?php
                $curauth = (isset($_GET['author_name'])) ? get_user_by('slug', $author_name) : get_userdata(intval($author));
                ?>
                
                <?php 
                $wp_query->query_vars['page'] > 1 ? $current = $wp_query->query_vars['page'] : $current = 1;

				query_posts( array(
					'post_type' => array('magazines'),
					'author' => $author,					
                    'posts_per_page' => 5,
                    'paged' => $current ) 
				);
				
				if (have_posts()) : ?>
            
                <h1><?php _e('Author : ','vergo');?><?php echo $curauth->display_name; ?></h1>
    
            <div style="clear: both;"></div>

			<div class="postauthor">
                            
                <!-- <h3><?php /*_e('About Author: ','vergo'); */?></h3> -->
                  
                <?php echo get_avatar($curauth->user_email, 90 ); ?>

                <p class="authordesc">
                    <?php _e('Website','vergo');?>: <a>user_url; ?>"><?php echo $curauth->user_url; ?></a><br/>
                    <?php echo $curauth->user_description; ?>
                </p>
                
            </div>
            
            <div style="clear: both;"></div>

      		<ul class="archivepost">
          
    			<?php while (have_posts()) : the_post(); ?>
                                              		
            		<?php get_template_part('/includes/post-types/archivepost');?>
                    
   				<?php endwhile; ?>   <!-- end post -->
                    
     		</ul><!-- end latest posts section-->
            
            <div style="clear: both;"></div>
            
					<div class="pagination"><?php pagination('&laquo;', '&raquo;'); ?></div>

					<?php else : ?>			

                        <h3>This author has not created any posts.</h3>
						
                        <?php get_search_form(); ?><br/>
					<?php endif; ?>

    </div><!-- end #core .eightcol-->

    <!-- #sidebar -->          
    
    <!--<div id="core_bg"></div>-->

</div><!-- #core -->

<!-- TEST ADDITION!!!!! -->
        
<!-- END OF TEST!!!! -->

<div id="rightsidebar" class="body2 snap-right-part-new">
    <?php if ( !function_exists('dynamic_sidebar') || !dynamic_sidebar("Right Sidebar") ) : ?>
    <?php endif; ?>
</div>

<?php get_footer(); ?>'

• This topic was modified 5 years, 1 month ago by Jan Dembowski. Reason: Moved to Fixing WordPress, this is not an Developing with WordPress topic

The page I need help with: [log in to see the link]