[Q&A] Service SES error smtp; 5.1.0 - Unknown address error 554-'5.7.1

This is due to a security control on the receiver's email server. This can only be dealt with at that end (e.g. by adding to an allow-list) and nothing can be done in AWS.

See https://repost.aws/knowledge-center/ses-resolve-emails-not-delivered and in particular the sections There's an issue with the email recipient's email address, There's an issue with the email recipient's server and Your email is getting labeled as spam.

And also the section Check for sending issues from Amazon SES to the recipient domain of https://repost.aws/knowledge-center/ses-unable-receive-email

Hi,, you should check the destination address of this bounced email: it is either sent to a DNS domain name (i.e name after the @ sign for recipient) that doesn't exist or for which a mail server doesn't exist or is improperly set up.

The simplest way to check is to send manually from an email web mailbox (Gmail, Outlook, etc.) to same address and see what happens: you should also receive same kind of error message if issue is on receiving side.

Otherwise it may be in your SES setup: in that case, this guidance will help you https://repost.aws/knowledge-center/ses-unable-receive-email

Hope it helps!

Didier