Apex domains cannot have CNAME records.
Question and response
Question
dig telusmobility.com. NS
Answer
telusmobility.com. 5 NS dns8.telus.com.
telusmobility.com. 5 NS dns8.telus.ca.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0