Integration with Mailchimp not working

Hi, I have a signup form to access some gated content set up here, which should be correctly set up with my Mailchimp tags - but it says that it’s not secure when I submit test submissions. Does anyone have any advice?

https://preview.webflow.com/preview/recruiting-from-scratch?utm_medium=preview_link&utm_source=designer&utm_content=recruiting-from-scratch&preview=c5f75cb347ad40818a304d03b8b0161d&pageId=6557d0a8f771f2b79056aa4a&workflow=preview