[Forminator Pro] Mailchimp does not show up in forms

Hi best Support Team,
I am using forminator pro for the first time to gradually make the switch from gravity. This works great so far except the Mailchimp integration. On the respective Website I have included the Mailchimp registration in each form, but it does not show up. I am pretty sure that I am missing something fairly simple, so your kind advice is highly appreciated.

Have a great sunday and thanks a lot that you keep things moving even during the weekend.
All the best, Sebastian.

PS: php, WordPress, Theme & Plugins are uptodate, Server is well equipped, no errors so far with this website.