Replace unencrypted URL

[gramatschii]

Could someone please advise me how to fix this unencrypted url from Mailchimp?

It has https in it, so I'm not sure why its unencrypted ---->> https://gramatschii.us4.list-manage.com/subscribe/post?u=e6a3bdca8a31904802cafabf4&id=8fa7d7a88f

Thanks!