spf.aksend.net has no MX records.
Question and response
Question
dig spf.aksend.net. MX
Answer
The response has no answer records.
Authority
aksend.net. 3600 SOA ns21.cloudns.net. support.cloudns.net. 2025120104 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0