mail.pikx.com has no MX records.
Question and response
Question
dig mail.pikx.com. MX
Answer
The response has no answer records.
Authority
pikx.com. 60 SOA ns1.systemdns.com. hostmaster.systemdns.com. 1751977931 10800 3600 300 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0