vpn.oxfordnetworks.com has no MX records.
Question and response
Question
dig vpn.oxfordnetworks.com. MX
Answer
The response has no answer records.
Authority
oxfordnetworks.com. 3600 SOA dns1.firstlight.net. postmaster.no.email.please. 598392144 3600 600 2592000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0