mail158.stibee.com has no NS records.
NS records for this zone are defined at stibee.com.
NS records for this zone are defined at stibee.com.
Question and response
Question
dig mail158.stibee.com. NS
Answer
The response has no answer records.
Authority
stibee.com. 900 SOA ns-1656.awsdns-15.co.uk. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0