The problem is their security certificate. It is still new and hasn't been registered with a security verification company yet or the registration is just still pending.
Even with that status I inspected the cert and it is legitimate looking at this time with 256 bit AES encryption which is pretty standard. It actually shows a validity date of today so I would expect the warning to go away soon.
It can be an indicator of a fake cert but I would be willing to bet it is just cause it is new. AVE isn't a known scam site and no reason to think so just cause a cert issue...give it a couple days and I'm positive it will clear.