Sending 60k emails on the Amazon Simple Email service

Hello,

It may cause by email being filtered out by the recipients email services provider. What you will want to do next would be try to see what is in the bounce message. You can achieve this by https://go.aws/3mlZixy.

You can also check out this AWS troubleshooting document for some common issues: https://aws.amazon.com/premiumsupport/knowledge-center/ses-resolve-emails-not-delivered/

Regards,
Franky Chen