mail2.infinitynt.com.br has no CNAME records.
Question and response
Question
dig mail2.infinitynt.com.br. NS
Answer
The response has no answer records.
Authority
infinitynt.com.br. 8943 SOA ns134.prodns.com.br. root.srv134.prodns.com.br. 2026020504 86400 7200 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0