I am trying to integrate a Mailchimp sign up form with my website. I generated the form in Mailchimp and copied the embed code to my site. The problem is that my site has an
Short answer. No
Longer answer. No, you are stuck with that warning. You are posting to an unsecured site from a secured site and the user will get this notification.
I was also facing the same problem using default embed code provided by mailchimp, but that wasn't working on SSL site.
So after Googling for solution i found this link:
Stop MailChimp Forms Breaking Your SSL
https://www.ostraining.com/blog/coding/mailchimp-forms-ssl/
and it wasn't a big problem simply need to change the url from list-manage1.com to "list-manage.com"
simply need to test after removing 1 from the list-manage1.com and it worked fine after that.
It also works fine for post-json embed urls.
You can edit the form Mailchimp provide to embed so that it uses https and not http in the action url.
It's more work than a simple embed, but you can do this using the MailChimp API which has support for SSL. See the section entitled HTTPS / Secure Connections in the API docs.