ns.masterhost.RU has no CNAME records.
Question and response
Question
dig ns.masterhost.RU. NS
Answer
The response has no answer records.
Authority
masterhost.ru. 86 SOA ns5.masterhost.ru. hostmaster.masterhost.ru. 1 28800 7200 1209600 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0