mx.ntt.RU has no CNAME records.
Question and response
Question
dig mx.ntt.RU. NS
Answer
The response has no answer records.
Authority
ntt.ru. 2551 SOA ns.ntt.ru. george.ntt.ru. 20091587 86400 7200 3600000 172800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0