auth.frontiernet.net has no MX records.
Question and response
Question
dig auth.frontiernet.net. MX
Answer
The response has no answer records.
Authority
frontiernet.net. 3600 SOA auth.roch.ny.frontiernet.net. hostmaster.frontiernet.net. 2602100003 900 300 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0