Problem with WooCommerce Emails

I have a small webshop set up with woocommerce and recently added Mailpoet to the installation to automate an email sending additional info for the product which was purchased. For that I have set up a “Email sent when a customer buys product” Mail.

Testing the mail myself shows everything to work fine, but when a new customer places an order they don’t receive anything and the sent mail counter of the email in question doesn’t increase. Even after fully processing the order.

In the subscriber list all the new customers are listed as “Unsubscribed” without any associated lists, whereas the imported contact details from woocommerce are all listed as “subscribed” and part of the list “WooCommerce Customers”.

Can somebody tell me what I have done wrong with my setup? It looks to me that the only issue is new customers not being subscribed to the mailing list.