ariel.collegenet.com has no MX records.
Question and response
Question
dig ariel.collegenet.com. MX
Answer
The response has no answer records.
Authority
collegenet.com. 86400 SOA ns.collegenet.com. postmaster.collegenet.com. 2014092240 600 900 604800 102701
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0