ext.airstreamcomm.net has no MX records.
Question and response
Question
dig ext.airstreamcomm.net. MX
Answer
The response has no answer records.
Authority
airstreamcomm.net. 86400 SOA ns1.airstreamcomm.net. airsys-alerts.wins.net. 2026011403 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0