mail.nvhost.ru has no CNAME records.
Question and response
Question
dig mail.nvhost.ru. NS
Answer
The response has no answer records.
Authority
nvhost.ru. 1543 SOA nvhostnew.ru. root.nvhostnew.ru. 2013113340 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0