dns20.telus.ca has no CNAME records.
Question and response
Question
dig dns20.telus.ca. NS
Answer
The response has no answer records.
Authority
telus.ca. 3600 SOA dns48.telus.com. dnsadmin2.telus.com. 2019276716 900 90 3600000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0