smtp.vic.svc.cloud.telstra.com has no CNAME records.
Question and response
Question
dig smtp.vic.svc.cloud.telstra.com. NS
Answer
The response has no answer records.
Authority
telstra.com. 346 SOA adns05.bigpond.com. hostmaster.telstra.net. 2026030903 7200 1800 7200000 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0