dns-rc.aws.oath.cloud has no MX records.
Question and response
Question
dig dns-rc.aws.oath.cloud. MX
Answer
The response has no answer records.
Authority
dns-rc.aws.oath.cloud. 900 SOA ns-1977.awsdns-55.co.uk. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0