Apex domains cannot have CNAME records.
Question and response
Question
dig support. NS
Answer
support. 5 NS v0n3.nic.support.
support. 5 NS v0n2.nic.support.
support. 5 NS v0n0.nic.support.
support. 5 NS v0n1.nic.support.
support. 5 NS v2n1.nic.support.
support. 5 NS v2n0.nic.support.
Authority
The response has no authority records.
Additional
v0n0.nic.support. 166923 A 65.22.20.5
v0n1.nic.support. 166973 A 65.22.21.5
v0n2.nic.support. 166923 A 65.22.22.5
v0n3.nic.support. 166923 A 161.232.10.5
v2n0.nic.support. 166923 A 65.22.23.5
v2n1.nic.support. 166923 A 161.232.11.5
v0n0.nic.support. 166923 AAAA 2a01:8840:16:0:0:0:0:5
v0n1.nic.support. 166973 AAAA 2a01:8840:17:0:0:0:0:5
v0n2.nic.support. 166923 AAAA 2a01:8840:18:0:0:0:0:5
v0n3.nic.support. 166923 AAAA 2a01:8840:f4:0:0:0:0:5
v2n0.nic.support. 166923 AAAA 2a01:8840:19:0:0:0:0:5
v2n1.nic.support. 166923 AAAA 2a01:8840:f5:0:0:0:0:5
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0