Apex domains cannot have CNAME records.
Question and response
Question
dig health. NS
Answer
health. 5 NS ns3.dns.nic.health.
health. 5 NS ns2.dns.nic.health.
health. 5 NS a.nic.health.
health. 5 NS c.nic.health.
health. 5 NS ns1.dns.nic.health.
health. 5 NS b.nic.health.
Authority
The response has no authority records.
Additional
a.nic.health. 98340 A 37.209.192.10
b.nic.health. 98340 A 37.209.194.10
c.nic.health. 98340 A 37.209.196.10
ns1.dns.nic.health. 98340 A 156.154.144.247
ns2.dns.nic.health. 98340 A 156.154.145.247
ns3.dns.nic.health. 98340 A 156.154.159.247
a.nic.health. 98340 AAAA 2001:dcd:1:0:0:0:0:10
b.nic.health. 98340 AAAA 2001:dcd:2:0:0:0:0:10
c.nic.health. 98340 AAAA 2001:dcd:3:0:0:0:0:10
ns1.dns.nic.health. 98340 AAAA 2610:a1:1071:0:0:0:0:f7
ns2.dns.nic.health. 98340 AAAA 2610:a1:1072:0:0:0:0:f7
ns3.dns.nic.health. 98340 AAAA 2610:a1:1073:0:0:0:0:f7
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0