ns3.byet.org has no MX records.
Question and response
Question
dig ns3.byet.org. MX
Answer
The response has no answer records.
Authority
byet.org. 86400 SOA ns1.byet.org. support.byet.org. 2010123002 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1680, xrcode 0, version 0, flags 0