Apex domains cannot have CNAME records.
Question and response
Question
dig net-city.net. NS
Answer
net-city.net. 5 NS ns2.net-city.net.
net-city.net. 5 NS ns3.net-city.net.
net-city.net. 5 NS ns1.net-city.net.
Authority
The response has no authority records.
Additional
ns1.net-city.net. 5 A 193.107.72.34
ns2.net-city.net. 5 A 193.107.72.35
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0