Is it possible to send email via the amazon ses smtp service with a iam role account?

Solution 1:

You can use this project to send SMTP without credentials using IAM role instead https://github.com/loopingz/aws-smtp-relay

Solution 2:

You can try to give your user the following permission. It seems redundant since you have already use wildcards, but the following policy works here (also with postfix) and is generated by AWS.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "ses:SendRawEmail",
      "Resource": "*"
    }
  ]
}