mail.infinitecampus.com has no MX records.
Question and response
Question
dig mail.infinitecampus.com. MX
Answer
The response has no answer records.
Authority
infinitecampus.com. 900 SOA blue.foundationdns.com. hostmaster.infinitecampus.com. 2025051516 1800 900 2419200 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0