Apex domains cannot have CNAME records.
Question and response
Question
dig citynet.works. NS
Answer
citynet.works. 5 NS ns2.chv.ua.
citynet.works. 5 NS ns3.chv.ua.
citynet.works. 5 NS ns.secondary.net.ua.
citynet.works. 5 NS ns1.chv.ua.
Authority
The response has no authority records.
Additional
ns1.chv.ua. 5 A 91.205.204.89
ns2.chv.ua. 5 A 91.205.204.90
ns3.chv.ua. 5 A 77.52.20.140
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0