Thanks for the quick reply @vini_brito. As you have mentioned it works when I statically add an email address.
Although in practice, I first have to identify the user by requesting the customer data object from stripe to be able to fetch the email from Bubble database and then send the email.
How can I solve this problem? Do I first have to create a separate workflow action that fetches the customer and then in the postmark action addd “Result of step …”?
Thanks