Apex domains cannot have CNAME records.
Question and response
Question
dig egstelecom.ru. NS
Answer
egstelecom.ru. 5 NS ns.egstelecom.ru.
egstelecom.ru. 5 NS ns1.egstelecom.ru.
egstelecom.ru. 5 NS ns3.egstelecom.ru.
Authority
The response has no authority records.
Additional
ns.EGSTELECOM.RU. 5 A 31.171.194.2
ns1.EGSTELECOM.RU. 5 A 31.171.194.10
ns3.EGSTELECOM.RU. 5 A 31.171.194.17
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0