mx02.exchange.telus.com has no NS records.
NS records for this zone are defined at exchange.telus.com.
NS records for this zone are defined at exchange.telus.com.
Question and response
Question
dig mx02.exchange.telus.com. NS
Answer
The response has no answer records.
Authority
exchange.telus.com. 3600 SOA dns41.telus.com. dnsadmin2.telus.com. 2018042421 900 7200 3600000 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0