Hi there @Giovanni,

Welcome to the Community!

I would love to know what errors you ran into specifically when you say it does not work.

You will need to install web tracking following the instructions in this help article: How to add web tracking to your Shopify site.  I’d recommend attempting to add the Klaviyo JS to your theme.liquid file in Shopify to see if that works.

Please make sure the code snippet included in this article is pasted at the bottom of your product.liquid theme file: How to Add Viewed Product Tracking. The guide has exact instructions on how to find this file. 

If you are using a Shopify 2.0 theme, there are actually separate steps that need to be followed in the section For Shopify 2.0 Themes. Otherwise, you can follow the steps in the section For All Other Themes.

Here are some things to check for:
 

1. Make sure that after adding the snippet into the product.liquid file or to a custom liquid section, that your changes are saved.
    
2. Make sure that the snippet is added into the currently active theme of the store - sometimes stores may have multiple themes available.
    
3. Otherwise, another possibility is that your theme uses a different template file instead of product.liquid. This is uncommon but may apply to your theme. You may want to check to see if product-template.liquid or product-form.liquid exist for your theme. Otherwise, you can check for other files with "product" in the name.
   
   This is also known to happen if you are using an app like PageFly since the app will change the default product page file being used by your store.

Once the "Viewed Product" script is properly installed, viewing a product page will trigger an event for your account so long as the current site visitor is identified.
There are three key ways Klaviyo will be able to identify a site visitor for web tracking purposes:

• If someone has, at some point, clicked through a Klaviyo email to your website
• If someone has, at some point, subscribed/opted-in through a Klaviyo form
• If someone has, at some point, logged into your site and you have identify tracking installed

Someone needs to have performed one of these actions in order to be tracked on your website for the purposes of tracking metrics such as Active on Site and Viewed Product.

Thanks!
Alex