Author posts not appearing for custom post type

Question

I have a custom post type setup called 'Blog' and I have added the ability to assign authors to posts.

I want to be able to display a list of posts made by an author, however the posts never appear for the custom post type, even though posts have been made by the author the loop always displays: 'No posts by this author.'

Here is the loop in my author.php file:

<?php $curauth = (isset($_GET['author_name'])) ? get_user_by('slug', $author_name) : get_userdata(intval($author)); ?>
<h1>Author: <?php echo $curauth->first_name; ?> <?php echo $curauth->last_name; ?></h1>

<!-- The Loop -->
<?php if ( have_posts() ) : while ( have_posts() ) : the_post(); 
    $postThumb = get_field( 'news_image' , $post->ID );
    $postThumb = $postThumb['sizes']['insightsPostThumb'];

    $cNewsBlogItem = array(
       'img'    => $postThumb,
       'title'  => $post->post_title,
       'date'   => date( 'd F, Y', strtotime( $post->post_date ) ),
                'link'  => get_permalink( $post->ID )
    );
?>
<?php
    if(!$cNewsBlogItem['img'] || $cNewsBlogItem['img'] == ""){
        // if no img use fallback
        $cNewsBlogItem['img'] = get_bloginfo('template_directory').'/images/news-fallback.jpg';
    }
?>

<a class="cNewsBlogItem <?php echo $cNewsBlogItem['class']; ?>" href="
<?php echo $cNewsBlogItem['link']; ?>" title="<?php echo $cNewsBlogItem['title']; ?>">

<img src="<?php echo $cNewsBlogItem['img']; ?>" alt="<?php echo $cNewsBlogItem['title']; ?>" />

Answer 1

I managed to resolve this issue by using pre_get_posts function and adding the custom post type to the main query.

I added the below to my functions.php file and now I get results for authors in my custom post type:

/* pre_get_posts function added to include post type blog in author loop */
  function add_cpt_author( $query ) {
    if ( !is_admin() && $query->is_author() && $query->is_main_query() ) {
    $query->set( 'post_type', array('post', 'blog' ) );
    }
  }
  add_action( 'pre_get_posts', 'add_cpt_author' );