spf.impsat.net has no MX records.
Question and response
Question
dig _spf.northwestmall.com. MX
Answer
The response has no answer records.
Authority
northwestmall.com. 3600 SOA ns1.northwestmall.com. dnsadmin.northwestmall.com. 2025092301 3600 600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0