cname.instatus.com has no MX records.
Question and response
Question
dig cname.instatus.com. MX
Answer
The response has no answer records.
Authority
instatus.com. 1800 SOA donovan.ns.cloudflare.com. dns.cloudflare.com. 2397334822 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0