I have 3 to 4 categories on my website. I am using WordPress search but when I am searching my category then I am getting

Nothing Found

also, I tried to search the subcategory then also I am getting the same message.

Would you help me out with this issue?

search.php

 <section id="primary" class="content-area mainSearch">
    <main id="main" class="site-main">
      <div class="equalPadding">
        <div class="cp-seeWrapper">
    <?php if ( have_posts() ) : 
          get_search_form();//search form
          ?>
          <div class="resultCount"><?php
          global $wp_query;
          echo $wp_query->found_posts.' RESULTS';
            ?></div>
         <div class="row">
      <?php 

       while (have_posts()){the_post();?>
        //displaying result here

       <?php } ?>

      <?php 
    else :
      get_template_part( 'template-parts/content', 'none' );

    endif;
    ?>
          </div>
    </div>
    </div>
    </main><!-- #main -->
  </section><!-- #primary -->