This seems to be caused by episerver edit mode loading content in frame, and the fact that the x-frame-options : sameorigin header is set by the mvc framework pr default

one solution could be to supress the xframeoptions header for all pages, edit mode or not

global.asax :

protected void Application_Start()
{
    AntiForgeryConfig.SuppressXFrameOptionsHeader = true;
}

 Another solution could be to remove the x-frameoptions header  when pages are in editmode, using a filter on those controllers loading content via https

public class XframeFilter: ActionFilterAttribute
    {
        public override void OnResultExecuted(ResultExecutedContext filterContext)
        {
            if (PageEditing.PageIsInEditMode)
            {
                filterContext.HttpContext.Response.Headers.Remove("x-frame-options");
            }
        }