Our security configuration is fine. Apple suggests that error message might be caused by your date/time being off, by 3rd party anti-malware products, or by a corrupt browser cache. In other words, they first blame you, then other companies... :).  I suggest you clear Safari's cache on your device. If you need specific directions on how to clear it on your device, you'll need to search... but no matter what you're using, it's an easy fix. Or you can simply ignore it.