yyz1.oracleemaildelivery.com has no MX records.
Question and response
Question
dig yyz1.oracleemaildelivery.com. MX
Answer
The response has no answer records.
Authority
yyz1.oracleemaildelivery.com. 300 SOA ns1.p68.dns.oraclecloud.net. hostmaster.yyz1.oracleemaildelivery.com. 731284 3600 600 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0