spfbl-backend.mailcorp.com.br has no SRV records.
Question and response
Question
dig spfbl-backend.mailcorp.com.br. SRV
Answer
The response has no answer records.
Authority
mailcorp.com.br. 300 SOA dns1.ctitech.net.br. postmaster.ctitech.net.br. 2026022502 28800 3600 604800 300
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0