gate.isp.net has no MX records.
Question and response
Question
dig gate.isp.net. MX
Answer
The response has no answer records.
Authority
isp.net. 3600 SOA gate.lasvegas.net. postmaster.lasvegas.net. 2025121616 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0