Ghost preview and portal dialogs not displaying

About a week ago I did a new install of Ghost using the pre-created DigitalOcean droplet. I’ve set up Stripe, Mailgun, and connected the site to my URL, using the basic Casper theme without any major changes, just some experimental tweaks to try to get the portal popup to appear. In the admin console, I don’t see any previews for the site nor do I see any previews when trying to edit the portal dialogs through. Any ideas or tips on how to debug or fix this? And how do I actually get the portal dialogs to display in the theme?

Ghost version - 3.39.3 (I know there’s a new minor version, but haven’t upgraded yet)
Digital Ocean - Ubuntu 18.04, 1GB memory, 25GB disk
The domain is hosted on Route 53.

There is a console error:
Mixed Content: The page at 'https://.../ghost/#/site' was loaded over HTTPS, but requested an insecure frame 'http://.../'. This request has been blocked; the content must be served over HTTPS.
I’m unsure how to force Ghost to fetch from HTTPS for the iframe though.

Hey there :wave:

It sounds like your Ghost URL is configured to be http but you’re using https. If you’re planning on using https, your Ghost URL must be set to https, otherwise you’ll run into issues like you’re seeing. Can you try setting the url to https (don’t forget to restart Ghost!) and seeing if the issue persists?

Thank you very much for the help!