bizns3.mail.RU has no NS records.
NS records for this zone are defined at mail.RU.
NS records for this zone are defined at mail.RU.
Question and response
Question
dig bizns3.mail.RU. NS
Answer
The response has no answer records.
Authority
mail.RU. 60 SOA ns1.mail.RU. hostmaster.mail.RU. 3565739367 900 900 604800 60
Additional
. 0 OPT ; payload 512, xrcode 0, version 0, flags 0