sap has no MX records.
Question and response
Question
dig sap. MX
Answer
The response has no answer records.
Authority
sap. 86400 SOA anycast9.irondns.net. dnsmaster.irondns.net. 2602231119 7200 7200 604800 7200
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0