blox.net.umd.edu has no MX records.
Question and response
Question
dig blox.net.umd.edu. MX
Answer
The response has no answer records.
Authority
net.umd.edu. 300 SOA blox.net.umd.edu. hostmaster.umd.edu. 115265107 14400 3600 2419200 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0