Apex domains cannot have CNAME records.
Question and response
Question
dig elcom.ru. NS
Answer
elcom.ru. 5 NS sai2.elcom.ru.
elcom.ru. 5 NS ns.elcom.ru.
Authority
The response has no authority records.
Additional
ns.elcom.ru. 5 A 84.53.200.7
sai2.elcom.ru. 5 A 84.53.199.250
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0