smtp.mbox.contact.bg has no NS records.
NS records for this zone are defined at mbox.contact.bg.
NS records for this zone are defined at mbox.contact.bg.
Question and response
Question
dig smtp.mbox.contact.bg. NS
Answer
The response has no answer records.
Authority
mbox.contact.bg. 1800 SOA pns-pw.contact.bg. hostmaster.btc-net.bg. 2021063000 7200 3600 604800 1800
Additional
The response has no additional records.