us-phoenix-1.ocs.oraclecloud.com has no MX records.
Question and response
Question
dig us-phoenix-1.ocs.oraclecloud.com. MX
Answer
The response has no answer records.
Authority
us-phoenix-1.ocs.oraclecloud.com. 300 SOA ns1.p78.dns.oraclecloud.net. hostmaster.us-phoenix-1.ocs.oraclecloud.com. 306259 3600 600 604800 1800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0