Your browser is probably blocking un-secure content
Some versions of recent browsers (FireFox/Chrome) will reject
HTTP content when the page is served over
HTTPS. This is to prevent insecure content being served alongside secure content.
So if you visit the homepage in Magento and specify
https:// in the URL, all the linked resources within the page source will still be
http:// - and the browser may reject loading that content to preserve security.
But if you've loaded the page once before, there's a good chance that some CSS/JS/Images may well already be in the browser cache, mitigating the requirement to fetch the resource remotely.
This can give the impression that it works on some machines and not on others. Where in reality - its not really working for anyone, its just that some users benefit from their historical browser cache.
Self-signed certificates can also produce this exact behaviour.
Magento won't use HTTPS on the Homepage by default
Magento doesn't want/need to serve content over
https:// unless either
- The page warrants HTTPS (customer account, checkout etc.)
- You changed the unsecure base url to be HTTPS regardless
Under normal situations, there simply isn't a requirement for the homepage to be served over HTTPS - and if your unsecure base url is just
http:// - then Magento will still continue to load un-secure resources.
So if you want HTTPS on your homepage, either change core code to dictate whether the area needs to be secure or not - or make the entire site HTTPS regardless.
Its normal, don't worry
Basically, what you are seeing is normal behaviour - on the front-end at least. Just because you want HTTPS on the homepage, doesn't mean Magento will serve everything to you with HTTPS.
Its more concerning what is happening with your back-end, but again, if you haven't actually enabled "Use Secure URLs in Admin" and defined a
https:// URL for the "Base Secure URL" - then again, what you see is normal.
If you want HTTPS, ensure you enable in the front-end/back-end as appropriate and set the "Base Secure URL" to suit.