smtp-gw.cybersource.com has no MX records.
Question and response
Question
dig smtp-gw.cybersource.com. MX
Answer
The response has no answer records.
Authority
cybersource.com. 300 SOA lloyd.ns.cloudflare.com. dns.cloudflare.com. 2019104002 10000 2400 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0