spf.computec.com has no MX records.
Question and response
Question
dig spf.computec.com. MX
Answer
The response has no answer records.
Authority
computec.com. 21600 SOA ns1.impsat.net.co. hostmaster.impsat.net.ar. 2220831314 10800 3600 604800 21600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0