spf4.ucdavis.edu has no MX records.
Question and response
Question
dig spf4.ucdavis.edu. MX
Answer
The response has no answer records.
Authority
ucdavis.edu. 900 SOA ns0105.secondary.cloudflare.com. netadmin.ucdavis.edu. 118868780 10800 300 2419200 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0