drz1.oracleemaildelivery.com has no MX records.
Question and response
Question
dig drz1.oracleemaildelivery.com. MX
Answer
The response has no answer records.
Authority
drz1.oracleemaildelivery.com. 300 SOA ns1.p202.dns.oraclecloud.net. hostmaster.drz1.oracleemaildelivery.com. 126315 3600 600 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0