Apex domains cannot have CNAME records.
Question and response
Question
dig ops-netman.net. NS
Answer
ops-netman.net. 5 NS ns01-6.ops-netman.net.
ops-netman.net. 5 NS ns01.ops-netman.net.
ops-netman.net. 5 NS puck.nether.net.
ops-netman.net. 5 NS ns02.ops-netman.net.
ops-netman.net. 5 NS ns03.ops-netman.net.
Authority
The response has no authority records.
Additional
ns01.ops-netman.net. 5 A 144.202.128.36
ns02.ops-netman.net. 5 A 199.168.90.119
ns03.ops-netman.net. 5 A 104.244.14.254
ns01.ops-netman.net. 5 AAAA 2606:700:e:20:0:0:0:1
ns02.ops-netman.net. 5 AAAA 2606:700:e:550:b00b:0:0:b00b
ns03.ops-netman.net. 5 AAAA 2620:11c:f008:0:0:0:0:254
ns01-6.ops-netman.net. 5 AAAA 2606:700:e:550:b00b:0:0:1234
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0