cust.sover.net has no MX records.
Question and response
Question
dig cust.sover.net. MX
Answer
The response has no answer records.
Authority
cust.sover.net. 3600 SOA dns1.firstlight.net. postmaster.no.email.please. 627008722 3600 600 2592000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0