smtp2.digiservers.com.br has no CNAME records.
Question and response
Question
dig smtp2.digiservers.com.br. NS
Answer
The response has no answer records.
Authority
com.br. 244 SOA a.dns.br. hostmaster.registro.br. 2026054394 1800 900 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0