_spf.secomtrust.net has no MX records.
Question and response
Question
dig _spf.secomtrust.net. MX
Answer
The response has no answer records.
Authority
secomtrust.net. 300 SOA ns01.secomtrust.net. root.secomtrust.net. 2026021800 1800 900 1209600 300
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0