Convert HTTP_Request2 to wp_remote_post

The issue might be with how you’re passing the XML data in the request body. In the wp_remote_post function try this”

    $xmlCustomerDataByAuthorLicenseID = '<GetCustomerDataByAuthor><AuthorID>ABC123</AuthorID></GetCustomerDataByAuthor>';

$response = wp_remote_post(
    $urlCustomerDataByAuthor,
    array(
        'method' => 'POST',
        'headers' => array(
            'Content-Type' => 'text/xml'
        ),
        'body' => $xmlCustomerDataByAuthorLicenseID,
        'sslverify' => false
    )
);

if (wp_remote_success($response)) {
    $xmlDataParsed = simplexml_load_string($response['body']);

    foreach ($xmlDataParsed->{"Customer"} as $individualCustomer) {
        $customerEmail = strtolower(trim($individualCustomer->Email));
    }
}