Apex domains cannot have CNAME records.
Question and response
Question
dig DTLN.RU. NS
Answer
dtln.ru. 5 NS ns0.dtln.ru.
dtln.ru. 5 NS ns2.dtln.ru.
Authority
The response has no authority records.
Additional
ns0.DTLN.RU. 5 A 178.20.234.206
ns2.DTLN.RU. 5 A 95.131.31.206
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0