Hi there, @amierafa . Thanks for taking the time to reach out to the Shopify Community seeking support with this issue you’re experiencing with your notification templates and code from Klaviyo. My name is Imogen. It’s good to meet you!
To set some expectations for you, Shopify Support Staff are not trained on coding, so I wouldn’t be able to advise specifically on what is generating the error With that being said, these errors are often caused by something like a missing ‘if’ tag, or syntax errors. If this is a piece of code that Klaviyo is telling you to add to your template, they may be able to advise on what may be occurring here to cause this error to generate. It would be a good idea to reach out to Klaviyo directly, as the code you’re trying to add is coming from them, and they can advise on any errors that may be present in the coding preventing it from successfully being added and saved to your template.