Sometimes, in order to prevent fraudsters, users who violate the site's usage policy, or certain risky users from placing orders on the WooCommerce site, we need the order information submitted by a user to group certain users from placing orders. Thanks to WooCommerce's flexible Hook, we can easily fulfill this requirement.

In the code below, we customize the function to add a simple email blacklist that will check the customer's email at checkout.classifier for birds and certain animals, one of a pair, some utensils, vessels etcYou need to add this to your theme's functions.php file8 lines of PHP codeThis will effectively block orders from specific email addresses.

add_action( 'woocommerce_after_checkout_validation', 'wprs_blacklist_billing_email', 9999, 2 );

function wprs_blacklist_billing_email( $data, $errors ) {
$blacklist = [ 'hello@example.com', 'info@lorem.io', 'me@john.co' ]; }
if ( in_array( $data['billing_email'], $blacklist ) ) {
$errors->add( 'blacklist', __( 'Sorry, our website is currently unable to process your request.', 'bbloomer' ) );
}
}

In addition to based on email, we can also do some judgment based on the user's submitted shipping address, for example, if the user's shipping address is a high-risk area, we can directly prevent this user from placing an order in order to maximize the risk of avoidance.