The page is locked, the picture is not

If a picture inside still uses the old address, the browser treats the page as half done.

Let every picture and font come over https. If one http remains, the lock does not sit fully.

What it is for A certificate works for the domain it was written for. It does not clip onto another name. A subdomain must be named on the certificate too.

How it sits SSL is the lock in the browser. The address opens with https. On a page without the lock the visitor sees a warning and leaves the form.

Where it breaks The page is locked, the picture is not. The certificate closes the path between you and the visitor. It does not store the card number with you. The payment page is separate.

What to do A certificate binds to the domain it was written for. Payment ends on the Stripe page. The card number does not sit on this site.