alt3.aspmx.l.google.com.br has no CNAME records.
Question and response
Question
dig alt3.aspmx.l.google.com.br. NS
Answer
The response has no answer records.
Authority
google.com.br. 60 SOA ns1.google.com. dns-admin.google.com. 876632134 900 900 1800 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0