sna1.vpls.net has no MX records.
Question and response
Question
dig sna1.vpls.net. MX
Answer
The response has no answer records.
Authority
sna1.vpls.net. 38400 SOA ns1.vpls.net. support.vpls.net. 2025030300 10800 3600 604800 38400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0