Second loop on WordPress page not working

Disclaimer: I am trying to help someone with adding another section to their WordPress site. I did not write most of this code.

I am using a different custom post type for each WP_Query loop. Both loops work fine on their own, but when I try to run them on the same page, the second one doesn’t show any posts.

Things I have tried:

• wp_reset_query();
• wp_reset_postdata();
• changing the names of $query and $args so each is unique
• moving the reset function to inside if() (but still outside the while loop)

I have looked at every post I can find on the subject and tried all the suggestions, but nothing is working. Surely I am missing something.. Maybe another set of eyes can help me find the problem. I have posted the relevant code below.

/* ---- First Loop ---- */
<?php
    $args = array(
        'post_type'      => 'casestudies',
        'post_status'    => 'publish',
        'order'          => 'ASC',
        'posts_per_page' => -1
    );
                        
    $query = new WP_Query( $args );
    if ( $query->have_posts() ) :
        while ( $query->have_posts() ) : 
            $query->the_post();

            /* ---- Do Stuff ---- */

        endwhile;               
    endif;
    wp_reset_query();
?>

/* ---- Second Loop ---- */
<?php
    $args = array(
        'post_type'      => 'whitepages',
        'post_status'    => 'publish',
        'order'          => 'ASC',
        'posts_per_page' => -1
    );
                        
    $query = new WP_Query( $args );
    if ( $query->have_posts() ) :
        while ( $query->have_posts() ) : 
            $query->the_post();

            /* ---- Do Stuff ---- */    
                                
        endwhile;
    endif;
    wp_reset_query();
?>

Edit:

I found the solution with help from the accepted answer. I posted what I did to fix everything in another answer below.

Answer

Having just tried this code in my local environment, with the only change being the post_type values in you $args arrays, it seems to be working fine.

What I would recommend doing, as it is as follows:

1. Double checking the value for post_type matches the post type’s slug. This could just be a case of misspelling, and it’s something that tripped me up more times than I’d like to admit over the years.
   You can find this by going to functions.php and looking for register_post_type function calls.
2. Checking whether there are in fact published posts under that post type. Again, this is something I’ve been caught out by a few times too.

Additionally, you might want to think about perhaps neatening up the code a little, just to prevent potentially missing something and also to make it more manageable in the future.
Looping over an available post types array where you then construct a WP_Query for each of the available post types is my preference of going about a task like what you described, it looks like this:

<?php
    $post_types       = array( 'yourposttype', 'yourotherposttype' );
    $common_arguments = array(
        'post_status'    => 'publish',
        'order'          => 'ASC',
        'posts_per_page' => -1,
    );
?>

<?php foreach ( $post_types as $post_type ): ?>
    <?php
        $post_type_argument = array( 'post_type' => $post_type );
        $arguments          = array_merge( $common_arguments, $post_type_argument );
        $query              = new WP_Query( $arguments );
    ?>

    <?php if ( $query->have_posts() ): ?>
        <?php while ( $query->have_posts() ) : $query->the_post(); ?>

            <?php // Example output ?>
            <?php the_title(); ?>

        <?php endwhile; ?>
        <?php wp_reset_postdata(); ?>
    <?php endif; ?>
    
<?php endforeach; ?>

This way if you ever need to show another post type, you can add it to the $post_types array without having to duplicate blocks of code.

And finally, you were correct when you used wp_reset_postdata(), it’s the recommended function to run after looping over a custom WP_Query, wp_reset_query() is a little superfluous in this case.
You can read this answer by Stephen Harris for a bit more depth.