aws-mailserver104.pmweb.com.br has no CNAME records.
Question and response
Question
dig aws-mailserver104.pmweb.com.br. NS
Answer
The response has no answer records.
Authority
pmweb.com.br. 5854 SOA ns-1287.awsdns-32.org. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0