_spf.wiscmail.wisc.edu has no MX records.
Question and response
Question
dig _spf.wiscmail.wisc.edu. MX
Answer
The response has no answer records.
Authority
wiscmail.wisc.edu. 600 SOA adns1.doit.wisc.edu. hostmaster.doit.wisc.edu. 332 7200 1800 3628800 600
Additional
. 0 OPT ; payload 1220, xrcode 0, version 0, flags 0