Apex domains cannot have CNAME records.
Question and response
Question
dig ELTC.RU. NS
Answer
ELTC.RU. 5 NS ns2.ELTC.RU.
ELTC.RU. 5 NS ns.ELTC.RU.
Authority
The response has no authority records.
Additional
ns.ELTC.RU. 5 A 212.75.210.80
ns2.ELTC.RU. 5 A 212.75.211.5
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0