Hi there @Anthioshia23, 

Welcome to the Community! Happy to help! 

Klaviyo offers a few notification templates that are intended to be exported from Klaviyo and imported to Shopify. However, you will see this error if you try to use Klaviyo's product blocks in Shopify as our product blocks are Klaviyo specific and each platforms handles the HTML differently.

As a workaround, you can import the email templates via HTML into Shopify and then use Shopify's product block, however, I would recommend reaching out to Shopify Support so that they can assist you with inserting their product blocks after your export Klaviyo's templates into Shopify's platform. 

Thanks for participating in the Community!

-Taylor