REGIME_KEY_CLASSIFICATION_NOT_ACCEPTED

When it happens

The line's exemption_reason (or its absence) is not one AEAT accepts with its regime key: 04 needs reverse charge or an exemption; 08 only NO_SUJETA_LOCALIZACION at 0 %; 10 only NO_SUJETA_ART_7_9; 11 no reverse charge; 07 no reverse charge, no not-subject reason and only EXENTA_ART_20 or OTRO as exemptions.

How to fix it

Change the regime key or the exemption_reason of the line so the pair is one AEAT accepts.

Retry

Not as is: the same request fails the same way. Fix the cause described above, then send the request again, under a new Idempotency-Key if the body changed.

Returned by

The operations where this code is most likely. The list is not exhaustive.

• POST /v1/companies/{company_id}/invoices
• PATCH /v1/companies/{company_id}/invoices/{invoice_id}
• POST /v1/companies/{company_id}/invoices/{invoice_id}/issue

Rules that cite this code

• TAX-015 Regime key 08 means not subject to the line's tax
• TAX-017 Special regime keys carry the classification AEAT requires

Example response

When this error occurs, the API answers 422 Unprocessable Content with a JSON body of this shape:

{
  "type": "https://docs.beel.es/errors/REGIME_KEY_CLASSIFICATION_NOT_ACCEPTED",
  "title": "REGIME_KEY_CLASSIFICATION_NOT_ACCEPTED",
  "detail": "Regime key ‹value› does not accept a line with exemption_reason ‹value›: with that key AEAT only accepts exemption_reason ‹value›",
  "instance": "/v1/<resource>",
  "errors": [],
  "success": false,
  "error": {
    "code": "REGIME_KEY_CLASSIFICATION_NOT_ACCEPTED",
    "message": "Regime key ‹value› does not accept a line with exemption_reason ‹value›: with that key AEAT only accepts exemption_reason ‹value›",
    "details": {}
  },
  "meta": {
    "timestamp": "2026-05-21T10:00:00Z",
    "request_id": "4bf92f3577b34da6a3ce929d0e0e4736"
  }
}

The type URI is stable and always resolves to this page.

Message

Send the request with Accept-Language: <es|en|ca> to receive the message in your preferred language.

Placeholders like ‹value› are filled in at runtime with the actual values of your request.

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