Apex domains cannot have CNAME records.
Question and response
Question
dig center. NS
Answer
center. 5 NS v0n0.nic.center.
center. 5 NS v2n0.nic.center.
center. 5 NS v0n1.nic.center.
center. 5 NS v0n3.nic.center.
center. 5 NS v0n2.nic.center.
center. 5 NS v2n1.nic.center.
Authority
The response has no authority records.
Additional
v0n0.nic.center. 82330 A 65.22.28.4
v0n1.nic.center. 82330 A 65.22.29.4
v0n2.nic.center. 82330 A 65.22.30.4
v0n3.nic.center. 82330 A 161.232.14.4
v2n0.nic.center. 82330 A 65.22.31.4
v2n1.nic.center. 82330 A 161.232.15.4
v0n0.nic.center. 82330 AAAA 2a01:8840:1e:0:0:0:0:4
v0n1.nic.center. 82330 AAAA 2a01:8840:1f:0:0:0:0:4
v0n2.nic.center. 82330 AAAA 2a01:8840:20:0:0:0:0:4
v0n3.nic.center. 82330 AAAA 2a01:8840:f8:0:0:0:0:4
v2n0.nic.center. 82330 AAAA 2a01:8840:21:0:0:0:0:4
v2n1.nic.center. 82330 AAAA 2a01:8840:f9:0:0:0:0:4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0