Two issues seem likely:
- Your DNS changes haven’t propagated yet. It takes awhile for the DNS change to spread across the internet. Give it 1-2 hours and try again. [Hostgator recommends pointing your name servers to them.]
- If the issue remains, then check how your domain was entered into the quick installer. It’s possible that an extra
/is causing the whole thing to fail.
If neither of these is the culprit, then I’d suggest you contact their support team at https://helpchat.hostgator.com