Apex domains cannot have CNAME records.
Question and response
Question
dig dnsoperations.net. NS
Answer
dnsoperations.net. 3 NS ns3.ac1.lexsynergy.com.
dnsoperations.net. 3 NS ns2.ac1.lexsynergy.com.
dnsoperations.net. 3 NS ns4.ac1.lexsynergy.com.
Authority
The response has no authority records.
Additional
ns2.ac1.lexsynergy.com. 5 A 194.58.198.54
ns3.ac1.lexsynergy.com. 5 A 185.42.137.105
ns4.ac1.lexsynergy.com. 5 A 194.58.196.54
ns2.ac1.lexsynergy.com. 5 AAAA 2a01:3f1:3054:0:0:0:0:53
ns3.ac1.lexsynergy.com. 5 AAAA 2a01:3f0:400:0:0:0:0:54
ns4.ac1.lexsynergy.com. 5 AAAA 2a01:3f1:854:0:0:0:0:53
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0