AJAX function for checking the VAT number based on country and VAT id

simple-vies-check.php

<?php

add_action( 'wp_ajax_simple_vies_check', 'simple_vies_check' );
add_action( 'wp_ajax_nopriv_simple_vies_check', 'simple_vies_check' );

if ( ! function_exists( 'simple_vies_check' ) ) {
    /**
     * AJAX VIES check function for WooCommerce checkout
     *
     * @since 1.0.0
     */
    function simple_vies_check() {
        if ( isset( $_POST['tax_id'] ) && isset( $_POST['billing_country'] ) ) { // Input var okay.
            $tax_id          = isset( $_POST['tax_id'] ) ? sanitize_text_field( wp_unslash( $_POST['tax_id'] ) ) : ''; // Input var okay.
            $billing_country = isset( $_POST['billing_country'] ) ? sanitize_text_field( wp_unslash( $_POST['billing_country'] ) ) : ''; // Input var okay.

            try {
                $client = new SoapClient( 'http://ec.europa.eu/taxation_customs/vies/checkVatService.wsdl' );
                $response = $client->checkVat(array(
                    'countryCode' => $billing_country,
                    'vatNumber'   => $tax_id,
                ));
                if ( true === $response->valid ) {
                    wp_die( 'vies ok' );
                } else {
                    wp_die( 'vies null' );
                }
            } catch (Exception $e) {
                $error = $e->getMessage();

                $error_array = array(
                    'INVALID_INPUT'       => 'The provided CountryCode is invalid or the VAT number is empty',
                    'SERVICE_UNAVAILABLE' => 'The SOAP service is unavailable, try again later',
                    'MS_UNAVAILABLE'      => 'The Member State service is unavailable, try again later or with another Member State',
                    'TIMEOUT'             => 'The Member State service could not be reach in time, try again later or with another Member State',
                    'SERVER_BUSY'         => 'The service can\'t process your request. Try again latter',
                );

                if ( array_key_exists( $error , $error_array ) ) {
                    wp_die( wp_json_encode( $error_array[ $error ] ) );
                }
            }
        }
    }
}

Doesn't seem to be working in Woo 3.2.6. Is this lookup routine still valid?