Why is index.php displayed instead of single.php?

Question

WordPress

Hello!
I make my template on the Wordpress engine. I’m not strong in this, but I decided to try, so I do everything according to video lessons and information on the Internet. Stuck on displaying the post page. It seems that the URL changes and the page is reloaded, but index.php is displayed.
At the moment I have the following files associated with single.php:

• index.php
  
• single.php
  
• content.php
  
• content-single.php
  

Permalink settings: "Simple". All plugins are disabled. I am using WampServer.
Post output part of index.php:

<article>
        <?php
          $paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
          $temp = $wp_query;
          $wp_query = null;
          $wp_query = new WP_Query();
          $wp_query->query('showposts=2&post_type=post&paged='.$paged.'&cat=4');
          while ($wp_query->have_posts()) : $wp_query->the_post();
          //Content
            get_template_part('template-parts/content', get_post_format());
            wp_reset_postdata();
          endwhile;
        ?>
</article>

Code in content.php file in template-parts folder:

<div id="post-<?php the_ID(); ?>" <?php post_class('row new_article') ?>>
  <div class="col-xs-12 col-sm-4 col-xl-3 no-gutters">
    <?php if ( has_post_thumbnail() ) : ?>
      <a href="<?php the_permalink($post); ?>"><img class="post_thumbnails media-object" src="<?php the_post_thumbnail_url(); ?>" alt="Olaines 1.vidusskola - jaunumi"></a>
    <?php endif; ?>
  </div>
  <div class="col-xs-10 col-xs-push-1 col-sm-8 col-sm-push-0 col-xl-9">
    <h1 class="post_heading"><a href="<?php the_permalink($post); ?>"><?php the_title();?></a></h1>
    </br>
    <div class="excerpt">
      <?php the_excerpt(); ?>
    </div>
    <a href="<?php the_permalink($post); ?>"><button type="button" class="btn btn-primary"><?php echo get_theme_mod('main_readmore_button'); ?></button></a>
  </div>
</div>

All code in single.php in template-parts folder:

<?php get_header(); ?>
<!--Slider-->
  <?php
    get_template_part('template-parts/slider');
  ?>
<!--Slider-->
<div class="line_gradient"></div>

<div class="container-fluid" id="news">
  <div class="row">
    <!--Main (news)-->
    <div class="col-xs-12 col-sm-8">
      <img class="media-object" id="img_newspaper" src="<?php bloginfo("template_url"); ?>/images/newspaper.png" alt="Olaines 1.vidusskola - jaunumi">
      <h1 id="title_jaunumi"><?php echo get_theme_mod('main_news'); ?></h1>
      <div id="line_gradient_news_top" class="line_gradient"></div>
      <article id="post-<?php the_ID(); ?>" <?php post_class('new_article') ?>>
        <?php
          $temp = $wp_query;
          $wp_query = null;
          $wp_query = new WP_Query();
          $wp_query->query('showposts=2&post_type=post&cat=4');
          while ($wp_query->have_posts()) : $wp_query->the_post();

          //Content
          get_template_part('template-parts/content', 'single');

          wp_reset_postdata();
          endwhile;
        ?>
      </article>
      <div id="line_gradient_news_bottom" class="line_gradient"></div>
    </div>
    <!--Left sidebar-->
    <?php get_sidebar();  ?>
    <!--Left sidebar-->
  </div>
</div>
<?php get_footer(); ?>

All code in content-single.php in template-parts folder:

<div id="post-<?php the_ID(); ?>" <?php post_class('new_article row') ?> >
  <div class="col-xs-12 col-sm-4 col-xl-3 no-gutters">
    <?php if ( has_post_thumbnail() ) : ?>
      <img class="post_thumbnails media-object" src="<?php the_post_thumbnail_url(); ?>" alt="Olaines 1.vidusskola - jaunumi">
    <?php endif; ?>
  </div>
  <div class="col-xs-10 col-xs-push-1 col-sm-8 col-sm-push-0 col-xl-9">
    <h1 class="post_heading"><?php the_title();?></h1>
    </br>
    <div class="content">
      <?php the_content(); ?>
    </div>
  </div>
</div>

It seems that I'm doing everything right and content.php sees it, but single.php doesn't see it.
Thanks in advance for your help!

Answer 1

Most likely, you read the file up to the line get_template_part('template-parts/slider');and after receiving the error, nothing is reproduced further.
The error is that you are already in the template-parts folder, which means you are trying to access the template-parts / template-parts folder