cnxsmtpuk01.concentrix.com has no NS records.
NS records for this zone are defined at concentrix.com.
NS records for this zone are defined at concentrix.com.
Question and response
Question
dig cnxsmtpuk01.concentrix.com. NS
Answer
The response has no answer records.
Authority
concentrix.com. 300 SOA ns-cloud-e1.googledomains.com. cloud-dns-hostmaster.google.com. 591 21600 3600 259200 300
Additional
. 0 OPT ; payload 512, xrcode 0, version 0, flags 0