dns.octor.com has no NS records.
NS records for this zone are defined at octor.com.
NS records for this zone are defined at octor.com.
Question and response
Question
dig dns.octor.com. NS
Answer
The response has no answer records.
Authority
octor.com. 3600 SOA nh468-dns-2200-005.fetnet.net. please_set_email.absolutely.nowhere. 19 15 5 604800 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0