x4.eduneering.com has no MX records.
Question and response
Question
dig x4.eduneering.com. MX
Answer
The response has no answer records.
Authority
eduneering.com. 432000 SOA ns-1576.awsdns-05.co.uk. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0