Using the Display Order field to order categories on Knowledge Base page doesn't seem to work

I was working with the categories and wanted to use the category Display Order (sequencenumber) field to order the categories on the page, however the portal doesn’t seem to have access to it - see red text below:

My ‘Knowledge Base Home’ template:

 {% extends 'Layout 1 Column' %}

 {% block main %}

  {% include 'Page Copy' %}

  {% assign category_url = sitemarkers['Category'].url %}

  {% assign count = count | default: 0 %}

  {% assign categories = knowledge.categories | top_level: count | order_by: 'sequencenumber' %}

  {% if categories %}

    <div class="list-group unstyled">

    {% for category in categories %}

      <a href="{{ category_url | add_query: 'id', category.categorynumber }}" class="list-group-item">

        {{ category.title }}

      </a>

    {% endfor %}

    </div>

  {% endif %}

{% endblock %}

If I order by the title field, that works.