Why Anrok fails to compute tax and what address format it requires

Anrok requires a customer address to resolve the tax jurisdiction. If the address Lago sends is missing required fields, Anrok can't determine the applicable tax rate, and Lago emits a customer.tax_provider_error webhook.

How it works

Lago sends address_line_1, city, zip, and country to Anrok. It uses the customer's shipping address first, falling back to the billing address only when shipping address fields are entirely absent. If a shipping address is partially populated, for example only shipping_country set, Lago sends those partial fields rather than falling back to a complete billing address. This is the most common source of unexpected failures.

The minimum required fields differ by country, per Anrok's jurisdiction rules rather than Lago's own validation: US and Canadian customers need zip and country; customers in other countries generally need only country. state/region is not included in Lago's tax computation request to Anrok, so populating region alone will not unblock a failed tax call.

How to confirm the cause

Check the customer.tax_provider_error webhook payload for the error code and message Anrok returned. On the customer's profile, check both the billing and shipping address fields. If the shipping address is partially filled, that's likely what's being sent to Anrok.

How to resolve the issue

Make sure the customer's address is complete: if a shipping address is set, it needs at least zip and country (US/Canada) or country (other regions), otherwise clear the shipping address so Lago falls back to the billing address. After updating, click Refresh invoice on the draft to trigger a new Anrok tax computation.

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