No authoritative DNS Records

This means that a domain name has been delegated to a set of DNS Servers at the Registry, but those DNS servers do not hold any ‘authoritative’ DNS Records for that domain name.  For example, if yourname.co.nz had been delegated to ns.freeparking.co.nz and ns2.freeparking.co.nz at the Registry, but those DNS servers had no  ‘A’ or ‘MX’ Records for yourname.co.nz, this would result in all the Internet traffic looking for the location of yourname.co.nz receiving a DNS error.

DNS servers holding incorrect ‘authoritative’ Records

This is usually caused when a domain name is transferred from one Internet Provider to another, and the losing Provider does not remove their ‘authoritative’ DNS records.  For example, if the domain name yourname.co.nz had been hosted at Xtra (so Xtra held ‘authoritative’ DNS records for it) but then the DNS servers at the Registry were changed to WebFarm’s.  If Xtra did not remove their ‘authoritative’ DNS Records, all the people who connect to the Internet via Xtra, and therefore use Xtra’s DNS servers for direction, would still be sent in whatever direction Xtra’s DNS Servers pointed them, instead of being ‘referred’ to WebFarm’s DNS servers for the new (and valid) location of yourname.co.nz.

DNS ‘Time to Live’ and Caching

When a domain name is delegated to a new set of DNS Servers, or even when the DNS Records for a domain name are changed on the same set of DNS Servers, these changes take time to propagate through the Internet.  Propagation is the process where all of the other DNS Servers on the Internet ‘learn’ of the new ‘authoritative’ DNS Servers, or the new IP Address location of the website etc.  Propagation time can vary depending on what ‘time to live’ has been set on the previous authoritative DNS Records, or how long each ISP caches (saves) DNS Records they have ‘learnt’, before looking to see if a more up to date DNS Record exists.  Unfortunately, it is usually out of your control how long propagation of a DNS Server change takes, due to these ‘time to live’ and caching factors.   However, if you are making a change to a DNS Record, you can change the ‘time to live’ setting (and allow that time to propagate) before making the Record change, so that your changes propagate more quickly when they are made.