_spf1.pur3.net has no MX records.
Question and response
Question
dig _spf1.pur3.net. MX
Answer
The response has no answer records.
Authority
pur3.net. 3600 SOA ns0.dnssub.com. hostmaster.pure360.com. 2025102201 10800 1800 1209600 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0