_spf.dialhost.com.br has no MX records.
Question and response
Question
dig _spf.dialhost.com.br. MX
Answer
The response has no answer records.
Authority
dialhost.com.br. 3600 SOA ns1.dialhost.com.br. alerta.dialhost.com.br. 2026022200 3600 600 2219200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0