We'll create fresh WordPress site with Woo Custom Taxonomies Coupons installed. You have 20 minutes to test the plugin after that site we'll be deleted.
Apply Coupons to Custom taxonomies using the Woo Coupons System.
Discount type of Coupon must be the “Fixed cart discount”.
Download the zip folder and upload it as normal WordPress Plugin.
This plugin adds the ability to select one or multiple taxonomies including products categories, tags and custom taxonomies and applies the coupon