Why Lago shows 0% tax on invoice preview when the customer has no address (Anrok)

When you preview an invoice for a customer connected to Anrok who has no valid address, Anrok returns a customerAddressCouldNotResolve error. Lago handles this gracefully: the preview completes with 0% tax applied to all fees, and fires a customer.tax_provider_error webhook during preview. The fallback to zero tax is intentional.

The same underlying problem can also occur at customer creation. When you create a customer linked to an Anrok integration, Lago immediately calls Anrok to register the contact, and if the customer has no address yet, Anrok may return the same error, this time producing a customer.accounting_provider_error webhook instead. Watch for both webhook types if you're building error monitoring.

How to confirm the cause

Check for a customer.tax_provider_error webhook (invoice preview) or a customer.accounting_provider_error webhook (customer creation), and confirm the customer has no complete address.

How to resolve the issue

Anrok can't resolve a tax jurisdiction without a valid address in either case. Give the customer a complete address (country, and state or region if required by Anrok for that jurisdiction) via PUT /api/v1/customers/:external_id before creating them or generating invoices. Once the address is set, subsequent invoice previews and finalized invoices calculate tax correctly.

This article reflects guidance drawn from customer case resolutions. It is not officially supported documentation and may not apply to all situations.