I have a contact form from BM Content Builder. The contact form is set up as a “Subscribe Box”. I have made the connection with WP mail SMPT. When someone subscribes via the Contact Form, I receive an email with their email address in the body, but they do not receive a confirmation of subscription. How can I set up the subscription confirmation? I have some people subscribed multiple times (up to 20/30) because they do not receive any confirmation upon subscribing.