Products of specific brands

i want to show all products of a specific brand on a landing page and want to use the shortcode from the documentation “Products of specific brands” but it always show me all products listed in my online shop.
https://github.com/quadlayers/perfect-woocommerce-brands/wiki/Shortcodes#products-of-specific-brands
[products brands="dreyberg"]

i tried several brands but nothing changed.
am I doing something wrong?
does it work for you?

thank you in advance!
all the best!