prodmail4b.successfactors.com has no MX records.
Question and response
Question
dig prodmail4b.successfactors.com. MX
Answer
The response has no answer records.
Authority
successfactors.com. 3600 SOA ns1.sap.net. dns.sap-ag.de. 1771321098 3578 3600 2592000 300
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0