Are your controls within it allowing the postback? The page wizard is often used in Checkout so it requires each step to be 'valid' before continuing. There may be a one of the ecommerce web parts that's blocking the next step action because it's not valid yet.
https://docs.kentico.com/k10/custom-development/developing-web-parts/advanced-web-part-development-scenarios/connecting-web-parts-with-the-page-wizard