Every nameserver listed has A records. The NS records at all your nameservers are identical. Different autonomous systems OK. This is a must if you want to be found. DNS servers responded Good. MX MX Records Oh well, I did not detect any MX records so you probably don't have any and if you know you should have then they may be missing at your nameservers! The SOA record is: Primary nameserver: ns1.
Marina. Age: 28.
All of the NS records that your nameservers report seem valid.
Monroe. Age: 30.
DNS servers responded Good. The A records the GLUE got from the parent zone check are the same as the ones got from your nameservers. Missing nameservers reported by parent OK. It seems you are safe from a single point of failure.