An error occurred while trying to deliver the mail to mail.ru

When you receive the error message "An error occurred while trying to deliver the mail to the following recipients" for mail.ru addresses, this is a general delivery failure notification that can occur for various reasons. Here are some steps to troubleshoot and potentially resolve this issue:

1. Contact the recipient or mail.ru support to verify that the recipient's email address is correct and active, and inquire whether there have been any known delivery problems with mail.ru.

2. Check if the email might have been filtered as spam by mail.ru's systems rather than actually failing to deliver.

3. Consider that this might be a temporary delay rather than a permanent failure. Some ISPs, including mail.ru, might use greylisting to combat spam, which temporarily rejects emails from unknown senders. Amazon SES will automatically retry these messages, and they may be accepted on subsequent attempts.

4. Ensure your domain has proper email authentication records (DKIM, SPF, and DMARC) configured. This is especially important for successful email delivery to public email providers.

5. Monitor your sender reputation and ensure you're following best practices for email deliverability. Poor sender reputation can lead to your emails being rejected.

6. If you have a paid AWS Support Plan, consider opening a technical support case with AWS. Provide them with the recipient addresses and any request IDs or message IDs from your SendEmail or SendRawEmail responses.

7. Check if your IP address or domain has been blacklisted, which could cause delivery failures to certain email providers.

8. Review your SES suppression list to ensure the recipient addresses aren't listed there.

Without more specific error details, these general troubleshooting steps should help identify and resolve the issue with mail.ru deliveries.
Sources
Amazon SES Delivery problems - Amazon Simple Email Service
Amazon SES Delivery problems - Amazon Simple Email Service
getting "An error occurred while trying to deliver the mail to the following recipients" error | AWS re:Post
Amazon SES mailer daemon delivery status notification (failure). An error occured while trying to deliver mail to following recipent. From Gmail to Gmail wia SES. | AWS re:Post