Why isn't my shopify zap triggering for new customer accounts?

I created a Zap to connect my Shopify store with my Cloud Firestore database. The process is as follows: 1. A new customer account is enabled through my Shopify store.2. The login email is compared to a Firestore collection to check if it belongs to an existing user.3. A new document for that user is created in a Cloud Firestore collection, containing the Shopify customer information.I have tested and published this Zap without errors. However, it only triggers during testing in Zapier. In step 1 (Customer Account Enabled > Test > Continue with selected record), the Zap runs successfully when tested with any existing customer records.