ns2.bisv.ru has no CNAME records.
Question and response
Question
dig ns2.bisv.ru. NS
Answer
The response has no answer records.
Authority
bisv.RU. 8706 SOA ns1.bisv.RU. support.bisv.RU. 2026030601 86400 900 1857600 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0