There are tens of thousands of DNS servers on the Internet [if not more].
With regards to your specific DNS request, their replies can be grouped into five distinct categories:
- You've reached an authoritative DNS server for that zone and it replies as such.
- You've reached a DNS server that is not authoritative for that zone and can recursively reach the answer for you and does so - returning a non-authoritative result.
- You've reached a DNS server that is not authoritative for that zone and refuses to recursively look for the answer for you - it returns "Query Refused".
- You've reached a DNS server that is not authoritative for that zone and is nice enough to point you in the right direction - and it returns some root hints towards your requested zone.
- You reached a non-working DNS server and your querries will go unanswered.
You seem to be doing #2.
When you should be doing #1.