syd1.oracleemaildelivery.com has no MX records.
Question and response
Question
dig syd1.oracleemaildelivery.com. MX
Answer
The response has no answer records.
Authority
syd1.oracleemaildelivery.com. 300 SOA ns1.p68.dns.oraclecloud.net. hostmaster.syd1.oracleemaildelivery.com. 723797 3600 600 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0