AWS SES multiple values for MX record MAIL FROM

Question

I have SES domains in 2 regions, let's say test.example.com. I want to configure a custom MAIL FROM domain for them, like mail.test.example.com. I create an MX record in Route53 in test.example.com hosted zone with this content:

mail.test.example.com MX Simple 10 feedback-smtp.us-east-1.amazonses.com
                                10 feedback-smtp.us-east-2.amazonses.com

I suppose it should be routed approximately equally to both regions. Instead, for us-east-1 region MAIL FROM validation is passing, for us-east-2 is failing. Can anyone advise on the issue? The SES domains themselves are both verified.

Answer 1

https://docs.aws.amazon.com/ses/latest/DeveloperGuide/mail-from.html

See the note in point 6 in above doc.

“ To successfully set up a custom MAIL FROM domain with Amazon SES, you must publish exactly one MX record to the DNS server of your MAIL FROM domain. If the MAIL FROM domain has multiple MX records, the custom MAIL FROM setup with Amazon SES will fail.”

This custom mail from is only used for dmarc pass etc so you can always specify a different mail from in different region.