Great thanks, I had the wrong port number.
I have made a small change, can you now test this and confirm it is working for you?
My amends for reference:
Inside the file: /swift-framework/includes/page-builder/shortcodes/recent-posts.php
Locate this line:
$category_id = get_cat_ID( $category_slug );
Change to:
$category_id = get_category_by_slug( $category_slug );
Thanks.