Normally when you do the Register Application step it creates two files. One for http and one for https. When I checked your account the https one was missing, so that's why it worked over http, but not https. To fix it I copied the http setting over to the https virtualhost and restarted apache. The reason I think it happened is you probably added that domain, and then quickly registered the application prior to autossl running and setting up ssl for that domain. Since the https virtualhost didn't exist at the time register application couldn't create both records like it normally does. To fix it yourself you probably could have just ran the register application step of the guide again, and waited two hours for apache to restart. To prevent it from happening in the future, just make sure ssl is working before you register the application.