_spf.umd.edu has no MX records.
Question and response
Question
dig _spf.umd.edu. MX
Answer
The response has no answer records.
Authority
umd.edu. 300 SOA blox.net.umd.edu. hostmaster.umd.edu. 2895572790 14400 3600 2419200 300
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0