_dmarc.semcabo.com has no MX records.
Question and response
Question
dig _dmarc.semcabo.com. MX
Answer
The response has no answer records.
Authority
semcabo.com. 38400 SOA dns1.semcabo.pt. mail.semcabo.com. 1163576284 10800 3600 604800 38400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0