net.unitedlayer.com has no MX records.
Question and response
Question
dig net.unitedlayer.com. MX
Answer
The response has no answer records.
Authority
net.unitedlayer.com. 10800 SOA ns1.unitedlayer.com. ed.unitedlayer.com. 2018040401 21600 3600 604800 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0