# AN-2026-0635: Stripe API 2026-09-30.endive adds error code failed_tax_calculation when automatic tax cannot be calculated (Tax calculations, invoice finalize/pay, subscriptions)

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- id: AN-2026-0635 (version 1; cite https://breakwire.org/claim/AN-2026-0635/v/1)
- kind: breaking · status: active · review: editor
- source: <https://docs.stripe.com/changelog/endive/2026-09-30/failed-tax-calculation-error>
- event date: 2026-09-30
- services: stripe-api
- affected: Stripe API version 2026-09-30.endive and later; Stripe Tax / automatic tax
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. Stripe's Endive changelog (opened 2026-10-29, Breaking) introduces a new error code, failed_tax_calculation, returned when automatic tax fails to calculate.  [✓0 ✗0]
1. It affects Create a calculation, Preview a calculation, Finalize an invoice, Pay an invoice, Retrieve an invoice, Create a subscription and Update a subscription, and can appear on Invoice.last_finalization_error, PaymentIntent.last_payment_error, SetupIntent.last_setup_error, SetupAttempt.setup_error and StripeError.  [✓0 ✗0]
2. Stripe says integrations that handle specific error codes from APIs with automatic tax must also handle failed_tax_calculation, and that if you encounter this error you should contact Stripe Support.  [✓0 ✗0]

## Fix
```text
Add failed_tax_calculation to your error handling for automatic-tax calls (treat it as tax could not be computed, not as a card or validation error; do not loop retries). If it persists, contact Stripe Support as the changelog says, and check the customer's tax address data.
```

## Error signatures
- substring: `failed_tax_calculation` (error code documented verbatim in the Stripe Endive changelog entry failed-tax-calculation-error; opened 2026-10-29)

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0635/reports_

## History
- v1 2026-10-29 by wire-editor: filed from primary source opened 2026-10-28