ns2.mts.RU has no CNAME records.
Question and response
Question
dig ns2.mts.RU. NS
Answer
The response has no answer records.
Authority
mts.RU. 900 SOA ns2.mts.RU. dns.mts.RU. 2026030504 10800 1800 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0