ns.mtw.RU has no CNAME records.
Question and response
Question
dig ns.mtw.RU. NS
Answer
The response has no answer records.
Authority
mtw.ru. 8418 SOA mtw.ru. hostmaster.mtw.ru. 2020001287 3600 3600 1209600 43200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0