mail.4trust.com.br has no CNAME records.
Question and response
Question
dig mail.4trust.com.br. NS
Answer
The response has no answer records.
Authority
4trust.com.br. 10800 SOA ns1.4trust.com.br. root.4trust.com.br. 2025090802 10800 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0