# SERIES_NUMBER_COLLISION

The number assigned by the series is already in use. Please contact support: the series numbering needs review

<Callout type="info">
**Category:** [Invoices](/errors/category/invoicing)
</Callout>

| | |
|---|---|
| HTTP status | `400` Bad Request |
| Retry | No |

## When it happens

At issue time, the number the series would assign is already used by another invoice of the same company, in this series or in another one. Nothing is issued and no number is consumed.

## How to fix it

Retrying gives the same result: the series needs review. Contact support with the series and the invoice.

## Retry

Do not retry. The outcome is final: sending the same request again gets the same answer.

## Returned by

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

- [`POST /v1/companies/{company_id}/invoices`](/invoices/createCompanyInvoice)
- [`POST /v1/companies/{company_id}/invoices/{invoice_id}/issue`](/invoices/issueCompanyInvoice)
- [`POST /v1/companies/{company_id}/invoices/{invoice_id}/corrective`](/invoices/createCompanyCorrectiveInvoice)
- [`POST /v1/companies/{company_id}/invoices/{invoice_id}/convert-to-invoice`](/proforma/convertCompanyProformaToInvoice)

## Rules that cite this code

- [NUM-002 · An issued number is never reused, even when the invoice is voided](/rules/numbering#num-002)

## Example response

When this error occurs, the API answers `400` Bad Request with a JSON body of this shape:

```json
{
  "type": "https://docs.beel.es/errors/SERIES_NUMBER_COLLISION",
  "title": "SERIES_NUMBER_COLLISION",
  "detail": "The number assigned by the series is already in use. Please contact support: the series numbering needs review",
  "instance": "/v1/<resource>",
  "errors": [],
  "success": false,
  "error": {
    "code": "SERIES_NUMBER_COLLISION",
    "message": "The number assigned by the series is already in use. Please contact support: the series numbering needs review",
    "details": {}
  },
  "meta": {
    "timestamp": "2026-05-21T10:00:00Z",
    "request_id": "4bf92f3577b34da6a3ce929d0e0e4736"
  }
}
```

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

## Message

<Tabs items={["English", "Spanish", "Catalan"]}>
  <Tab value="English">{"The number assigned by the series is already in use. Please contact support: the series numbering needs review"}</Tab>
  <Tab value="Spanish">{"El número asignado por la serie ya está en uso. Contacte con soporte: la numeración de la serie requiere revisión"}</Tab>
  <Tab value="Catalan">{"El número assignat per la sèrie ja està en ús. Contacteu amb suport: la numeració de la sèrie requereix revisió"}</Tab>
</Tabs>

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

## Other errors in this category

<div className="grid grid-cols-2 gap-3 not-prose">
  <Card title="ATTACH_SOURCE_INVOICE_UNAVAILABLE" description="A source invoice is not available (it does not exist or you no longer have access); uncheck the source invoices attachment to send without the folder" href="/errors/ATTACH_SOURCE_INVOICE_UNAVAILABLE" />
  <Card title="ATTACH_SOURCE_INVOICES_NO_SOURCES" description="The invoice has no consolidation disbursements: there are no source invoices to attach" href="/errors/ATTACH_SOURCE_INVOICES_NO_SOURCES" />
  <Card title="ATTACH_SOURCE_INVOICES_REQUIRES_PDF" description="Attaching the source invoices also requires attaching the invoice PDF" href="/errors/ATTACH_SOURCE_INVOICES_REQUIRES_PDF" />
  <Card title="ATTACH_SOURCE_PDF_MISSING" description="These source invoices have no generated PDF: ‹value›" href="/errors/ATTACH_SOURCE_PDF_MISSING" />
  <Card title="ATTACH_SOURCE_ZIP_TOO_LARGE" description="The source invoices ZIP (‹value› MB) exceeds the maximum sendable size (‹value› MB)" href="/errors/ATTACH_SOURCE_ZIP_TOO_LARGE" />
</div>

## Keep exploring

<div className="grid grid-cols-2 gap-3 not-prose">
  <Card title="All Invoices errors" description="Every code in this category in one table." href="/errors/category/invoicing" />
  <Card title="Error reference home" description="Browse every category or jump to the handling guide." href="/errors" />
</div>

---

Full OpenAPI spec: https://docs.beel.es/api/openapi