em3.oraclecloud.com has no MX records.
Question and response
Question
dig em3.oraclecloud.com. MX
Answer
The response has no answer records.
Authority
em3.oraclecloud.com. 600 SOA ns1.p201.dns.oraclecloud.net. hostmaster.oracle.com. 2026010708 7200 600 1209600 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0