Your DNS server, while giving a valid answer for the A record, doesn't correctly return that there isn't a result for other record types, like AAAA or CAA. You need to fix your DNS so that your domain name works before you can get a certificate (and before users can reliably get to your domain name).
Just how to fix it depends a lot on the DNS software in use, but pretty anything even halfway-recent should be handling it automatically. But it looks like you might be using Network Solutions for your DNS, which has had a lot of complaints by people around here since it seems like they don't actually know how to run a DNS server.
Here's a somewhat-recent thread about it: