smtp.tidc.telus.com has no CNAME records.
Question and response
Question
dig smtp.tidc.telus.com. NS
Answer
The response has no answer records.
Authority
tidc.telus.com. 600 SOA dns1.tidc.telus.com. tidc.telus.com. 2019041600 2800 1800 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0