Hi! I am building a headless Shopify store, and I am trying to add a back in stock function. I followed this article (https://help.klaviyo.com/hc/en-us/articles/360006565332-Shopify-Back-in-Stock-for-Developers) and I do get a successful API response
```
{ email: 'mail@gmail.com', success: true }
```
However, I dont see any confirmation mail or any confirmation inside Klaviyo. What could this be?
payload:
{
method: 'POST',
headers: { 'content-type': 'application/x-www-form-urlencoded' },
data: 'a=AccountID&email=email@gmail.com&platform=shopify&variant=4480426737717',
url: 'https://a.klaviyo.com/api/v1/catalog/subscribe'
}