ns4.westcon.com has no CNAME records.
Question and response
Question
dig ns4.westcon.com. NS
Answer
The response has no answer records.
Authority
westcon.com. 1800 SOA ns3.westcon.com. dnsadmin.westcon.com. 2026071613 43200 600 2419200 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0