mail.adweb.com.au has no CNAME records.
Question and response
Question
dig mail.adweb.com.au. NS
Answer
The response has no answer records.
Authority
com.au. 3576 SOA q.au. hostmaster.donuts.email. 1772969463 7200 900 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0