Catchable fatal error: Object of class WP_Error

Question

Hi this is the code I am using on website, but it's giving me

Catchable fatal error: Object of class WP_Error could not be converted to string in /home/capritra/public_html/wp-content/themes/betheme/index.php on line 181

I have copied code from internet, it's working for people but not for me. Can someone help out?

 <?php
  $term_id = get_queried_object()->term_id;
  $taxonomy_name = get_query_var( 'cat' ); 
  $termchildren = get_term_children( $term_id, $taxonomy_name );

  // Loop through each child taxonomy term
  foreach ( $termchildren as $child ) {
      // Get the term object
      $term = get_term_by( 'id', $child, $taxonomy_name );

      // Get the values we need to output
      $url = get_term_link( $child, $taxonomy_name );
      $name = $term->name;

      // We make the call here to get the image and we pass in the term we want the image for
      $image = get_field('kategorija_slika', $term );

      // Output it all
      echo '<div class="col-sm-4 sub-caregory">';
      echo '<a href="' . $url . '">' . $name . '</a><div class="sub-caregory-image"><img src="' . esc_url($image['url']) . '" alt="' . esc_attr($image['alt']) . '" /></div>';
      echo '</div>';
  }
?>