Conditional post thumbnail based on logged status and post tag

Hey you have to use the below logic to handle the above conditions, it will work.

if (!is_user_logged_in() && has_tag('private')) { ?>

    <a href="https://wordpress.stackexchange.com/questions/368246/<?php the_permalink(); ?>" title="<?php the_title_attribute(); ?>">
        <img src="<?php bloginfo('template_directory'); ?>/img/default-login.jpg" alt="<?php the_title(); ?>" />
    </a>

<?php } else if( is_user_logged_in() && has_tag('private') ) {                  
    // show the actual featured image
    // check if the post has a Post Thumbnail assigned to it.
    if ( has_post_thumbnail() ) {
        the_post_thumbnail('news-thumb', 
        array('class' => 'news-thumb'));
    }
    //if you want to show the default image if featured image is not attached you can add here in else 
}else{
    ?>
         <a href="https://wordpress.stackexchange.com/questions/368246/<?php the_permalink(); ?>" title="<?php the_title_attribute(); ?>">
            <img src="<?php bloginfo('template_directory'); ?>/img/default.jpg" alt="<?php the_title(); ?>" />
        </a>

    <?php
}