VIES VAT Validation Blocked (IP_BLOCKED): Alternative VAT Validation in WooCommerce

VIES IP blocking and alternative VAT validation #

If your VAT validation log shows IP_BLOCKED, the VIES service has blocked your server’s IP, so EU/UK VAT Manager for WooCommerce cannot reach it. The workaround is to route validation through a third-party API, such as Vatlayer, with a code snippet that uses the alg_wc_eu_vat_validation_response filter, added with a plugin like Code Snippets.

The symptom #

VIES (VAT Information Exchange System), run by the European Commission, is the primary service for validating EU VAT numbers. When a server IP is blocked, validation returns failed or unknown responses and your log shows IP_BLOCKED.

The European Commission does not publish the exact criteria, but blocks often affect shared hosting or servers making high request volumes. Moving to a new host or IP can fix it but is usually impractical.

Workaround: route validation through a third-party API #

The plugin exposes the alg_wc_eu_vat_validation_response filter, which lets you replace the validation response with one from another service. The example below uses Vatlayer, which offers a free tier.

Step 1: install a snippet manager #

Add the code with a plugin such as Code Snippets so you do not edit your theme’s functions.php.

Step 2: add the snippet #

Create a new snippet and paste the code below. Replace the placeholder key with your own Vatlayer API key.

add_filter(
	'alg_wc_eu_vat_validation_response',
	function ( $response, $method, $country_code, $vat_number ) {
		$key = 'YOUR_KEY_HERE'; // set your Vatlayer key
		$url = "https://apilayer.net/api/validate?access_key={$key}&vat_number={$country_code}{$vat_number}";
		$curl = curl_init( $url );
		curl_setopt( $curl, CURLOPT_RETURNTRANSFER, 1 );
		curl_setopt( $curl, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4 );
		$res = curl_exec( $curl );
		curl_close( $curl );
		if ( $res ) {
			$res = json_decode( $res, true );
			$response = json_encode( array(
				'isValid'   => $res['valid'],
				'name'      => $res['company_name'],
				'address'   => $res['company_address'],
				'vatNumber' => $res['vat_number'],
			) );
		}
		return $response;
	},
	10,
	4
);

Step 3: test #

With the snippet active and your key in place, run a test validation on the checkout or in the plugin settings and confirm the number now validates.

Built-in alternative: VATSense #

For UK, Australian, Norwegian and Swiss numbers, the plugin already integrates VATSense. You can also enable Enable VATSense fallback on the Validation sub-tab (a VATSense API key is required) so VATSense is used when VIES is unavailable. See VATSense validation for UK and non-EU numbers.

Need a hand? #

Our team answers every ticket on the EU/UK VAT Manager support forum.