I know you haven’t had this issue in a while, but I’m having the same issue. I setup Ghost using the default Docker template in Portainer, and just like you everything worked and it’s just the preview. I’m using Nginx proxy and using LetsEncrypt too. But I’m not sure where to go to change the http to https. Is that in the docker container, or the site’s .json file? I only have a few files and a single .json file but it’s not a config.production.json file. Not sure where I’m supposed to look to edit it. Any help would be greatly appreciated!