I'm running Magento ver. 188.8.131.52. I have a multi-store configuration setup. They both use the same theme but they are in different folders with small tweaks like background images, logos, etc. So everything about the stores are identical. The first and main store functions fine. The second store also functions fine except when using SSL. The first store doesn't have any issues with SSL however the second gets a message about insecure content in the browser and the style isn't loaded at all.
http://shop.domain1.com - WORKS
https://shop.domain1.com - WORKS
http://shop.domain2.com - WORKS
https://shop.domain2.com - DOESN'T WORK
Any ideas what could be causing this on the second domain?
Magento will do the right thing with HTTPS on pages which it needs security on (like the cart and checkout pages) but won't neccessarily do the right them on pages where HTTPS is *not* required, like the homepage.
In this case, the HTTP URLs can end up in the block cache (if the first visitor to the homepage is over HTTP) and you may find insecure item warnings appear and disappear. If you're not running the *whole* site under HTTPS (by making the base_url start with https://) but you want to be able to view pages over HTTPS with working assets then you should make sure that your media, js and skin URLs in the config of each store also start with https://
Here's a screenshot showing what I mean:
I hope that helps,
I suspect that the CSS for "https://shop.domain2.com" is set as HTTP instead of HTTPS which is why it wouldn't load and the insecure content warning is shown in your browser.
You can view the page source and search for keywords like the following to confirm if this is the case:-