mx3.macau.ctm.net has no CNAME records.
Question and response
Question
dig mx3.macau.ctm.net. NS
Answer
The response has no answer records.
Authority
macau.ctm.net. 1906 SOA vassun1.macau.ctm.net. helpdesk.macau.ctm.net. 2016073723 86400 7200 2419200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0