spf.hosting-pf.net has no MX records.
Question and response
Question
dig spf.hosting-pf.net. MX
Answer
The response has no answer records.
Authority
spf.hosting-pf.net. 900 SOA ns4.mcnet.ad.jp. postmaster.mcnet.ad.jp. 2007120000 10800 900 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0