mailgroup.lastminute.com has no NS records.
NS records for this zone are defined at lastminute.com.
NS records for this zone are defined at lastminute.com.
Question and response
Question
dig mailgroup.lastminute.com. NS
Answer
The response has no answer records.
Authority
lastminute.com. 900 SOA ns-1907.awsdns-46.co.uk. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0