spf.mailpam.com has no MX records.
Question and response
Question
dig spf.mailpam.com. MX
Answer
The response has no answer records.
Authority
mailpam.com. 3600 SOA ns1.dnsimple.com. admin.dnsimple.com. 1503537966 86400 7200 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0