Apex domains cannot have CNAME records.
Question and response
Question
dig itoolabs.net. NS
Answer
itoolabs.net. 3 NS dns2.itoolabs.net.
itoolabs.net. 3 NS dns1.itoolabs.net.
itoolabs.net. 3 NS dns4.itoolabs.net.
Authority
The response has no authority records.
Additional
dns1.itoolabs.net. 3 A 109.69.176.1
dns2.itoolabs.net. 3 A 109.69.177.1
dns4.itoolabs.net. 3 A 176.9.82.149
dns4.itoolabs.net. 3 AAAA 2a01:4f8:151:2085:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0