smtp02.mts.am has no CNAME records.
Question and response
Question
dig smtp02.mts.am. NS
Answer
The response has no answer records.
Authority
mts.am. 600 SOA ns2.viva.am. ns.viva.am. 2026021201 3600 600 1296000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0