mail54.lebroch.com has no NS records.
NS records for this zone are defined at lebroch.com.
NS records for this zone are defined at lebroch.com.
Question and response
Question
dig mail54.lebroch.com. NS
Answer
The response has no answer records.
Authority
lebroch.com. 900 SOA ns-494.awsdns-61.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0