You may experience unusual behavior on your website if your SSL (secure domain name) does not match your actual domain name.  From a web browser's perspective you have two completely separate websites.  If settings seem to get lost when you click secure links, or add items to your shopping cart, what you are experiencing is a limitation of your web browser.  Browsers have a security feature built in to protect you from what's known as a Cross Domain vulnerability.

Basically, security in web browsers makes it so cookies and temporary internet files cannot be shared across domains.  In other words, one website cannot access the cookies and temporary internet files saved by another.

For example, the setting for Currency may reset back to its default when you click a secure link or vice versa.  Think of it this way... web browsers see it as if you have two websites, your visitors are browsing products on one website but paying (checking out) on another/different website.  So your customers may have to set some settings twice.  In this example, what your visitors will have to do is reselect the currency once they are on a shopping cart or checkout page (then both domains will display the same currency).  

Any reason you don't have an SSL for your domain?  

Shared SSL's are not ideal for ecommerce, and the industry experts have warned that it introduces a security risk.  Sharing an SSL certificate for multiple websites was more common many years ago, back when an SSL cert went for thousands of dollars, but today they are in the hundred dollar or less range.  Not having one for your domain might also affect shopper's confidence, if someone visits your website and looks at what's in the browser address bar it might be unsettling to some because it may look like they are giving their credit card or personal information to a company they have never heard of.  

What we'd recommend is that you Contact Us for assistance, we can assist you.