If you use the Shopify Search & Discovery app and want the filters to work with our app, please follow next instructions.
Navigate to Apps → EasySearch → Settings and enable the “Storefront filtering (powered by the Shopify Search & Discovery)” option:
Please note that collections containing over 5,000 products don't display filters. That’s the limitation on the filters’ side. In other words, the filters won't work with our app if the All Products collection (/collections/all) is used to show search results and such a collection includes over 5,000 products.