Group data in custom table not printed via shortcode

Hi Anh,

Yesterday I purchased a lifetime license and I am already having fun with the Meta Box plugin.
One thing that I am trying to figure out is to show the group data that is stored in a custom table via a shortcode. I am following your tutorial on how to create the shortcode and have this:

add_shortcode( 'dr_pricing', function() {
    $group = rwmb_meta( 'pricing_group' );
    if ( empty( $group ) ) {
        return '';
    }
    
    $output = '';
    
    // Sub-field Class.
    $groupclass = $group['group_class'] ?? '';
    $output .= '<h3 class="my-title">' . $groupclass . '</h3>';

    // Sub-field Number of Classes.
    $groupnumber = $group['number_of_classes'] ?? '';
    $output .= '<h3 class="my-title">' . $groupnumber . '</h3>';

    // Sub-field Price.
    $groupprice = $group['group_price'] ?? '';
    $output .= '<h3 class="my-title">' . $groupprice . '</h3>';

    // Sub-field No Classes.
    $noclass = $group['no_class'] ?? '';
    $output .= '<h3 class="my-title">' . $noclass . '</h3>';
    

    
    return $output;
} ); 

When I look in the custom database table I can see that the group data is stored as expected but it is not printed with shortcode [dr_pricing].
Do I need to alter the shortcode function to point to the custom database table? I could not find that piece of information in the tutorial or forum.

Thanks so much!