Display all subcategories from parent category

Question

I have 20 subcategories from a parent category, and they are like that
Parent

• September
• November
• … up to 20

Here is the code that try it to display, but I get only 1 category instead

<?php
$categories = get_categories('child_of=505');
foreach($categories as $category): ?>

    <div class="qitem">
        <a href="<?php get_category_link( $category->term_id ); ?>" title="<?php echo $category->name; ?>">
            <?php echo $category->name; ?>
        </a>
        <h4>
            <span class="caption">
                <?php echo $category->name; ?>
            </span>
        </h4>
        <p>
            <span class="caption">
                <?php echo $category->description; ?>
            </span>
        </p>
    </div>

<?php endforeach; ?>

Answer 1

get_categories() uses get_terms() so the array argument you can pass it will be the same.
From the documentation the array can have a property hide_empty, by default its true.
I'm guessing that those categories have no posts attached to it, if that is the case you will need to set it to false.
The code would be like this.

get_categories([
    'child_of'   => 505,
    'hide_empty' => false
]);

Update

If you want to order the results you can add order to the array, the default value is ASC so you will need to set it to DESC.

get_categories([
    'child_of'   => 505,
    'hide_empty' => false,
    'order'      => 'DESC'
]);

You can check WP_Term_Query::__construct( string|array $query = '' ) for all the available arguments you can use.