smtp-aws.utilibill.co.uk has no NS records.
NS records for this zone are defined at utilibill.co.uk.
NS records for this zone are defined at utilibill.co.uk.
Question and response
Question
dig smtp-aws.utilibill.co.uk. NS
Answer
The response has no answer records.
Authority
utilibill.co.uk. 300 SOA ns-cloud-e1.googledomains.com. cloud-dns-hostmaster.google.com. 15 21600 3600 259200 300
Additional
. 0 OPT ; payload 512, xrcode 0, version 0, flags 0