What are circumstances under which HTTPS resources (scripts? images? videos? iframes?) will fail to load inside of an HTTP page? The files are being served from IIS 8.5, and the problem occurred on multiple browsers. When the files are sent as HTTP, the page works properly.
I know the reverse (HTTP files onto HTTPS page) can be problematic for security reasons, but that shouldn't apply here, right?
Also, is it correct that Same Origin Policy only applies when scripting across multiple pages, and shouldn't affect files loading from the same server onto a single page?