// Amazon SES (AWS) instead php mail.
add_action( 'phpmailer_init', 'qr_aws_ses_smtp' );
function qr_aws_ses_smtp( $phpmailer ) {
    $phpmailer->isSMTP();
    $phpmailer->Host = 'email-smtp.us-east-1.amazonaws.com';
    $phpmailer->SMTPAuth = true;
    $phpmailer->Port = 25;
    $phpmailer->Username = 'AWS SES Credentials - username';
    $phpmailer->Password = 'AWS SES Credentials - password';
    $phpmailer->SMTPSecure = 'tls';
}