Hi ​@Alex974,

When you mention that the coupons don’t work in Prestashop, do you mean that when somebody enters the coupon on the checkout page and tries to apply it to their cart, it fails to do so? Or is something else happening?

Firstly, I’m assuming that the coupon (called Cart rule in Prestashop) has been created in Prestashop first, right? Cart rules need to be created in Prestashop before the coupon can be created in Klaviyo. Additionally, are you using version 1.5 or higher of the Klaviyo plugin in Prestashop? You can find the plugin version in Prestashop under Modules > Module Manager. 

Finally, do you notice any other issues with your Prestashop integration? Are orders, checkouts, and products syncing as expected? I’d like to rule out any large-scale Prestashop issues so we can ensure that the issues have to do with coupons and coupons only. Looking forward to your response!