mta01.testgt.net has no CNAME records.
Question and response
Question
dig mta01.testgt.net. NS
Answer
The response has no answer records.
Authority
testgt.net. 300 SOA ns-cloud-a1.googledomains.com. courrieraffaire.telus.com. 2 21600 3600 259200 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0