mx10.DHUB.RU has no CNAME records.
Question and response
Question
dig mx10.DHUB.RU. NS
Answer
The response has no answer records.
Authority
DHUB.RU. 659 SOA ns3.DHUB.RU. administrator.DHUB.RU. 357 900 600 86400 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0