---
title: sip_trunk.in_use
description: >-
  The workspace's SIP trunk still has numbers riding it and cannot be
  disconnected.
summary: >-
  Returned by DELETE /v1/sip-trunk when one or more BYO numbers still reference
  the trunk. Release those numbers first.
date: 2026-08-06T00:00:00.000Z
type: error
---


## Summary

`sip_trunk.in_use` means `DELETE /v1/sip-trunk` was refused because the trunk still has customer-owned numbers assigned to it.

## Cause

A number added via `POST /v1/numbers/byo` rides the workspace's own trunk for both signalling and billing. Deleting the trunk out from under a live number would strand it — the box would have nowhere to route its calls, and rating would have nothing to price them against. The platform mirrors the box's own interconnect-delete guard here: a trunk with numbers attached cannot be removed.

## Resolution

Release every BYO number on the trunk first:

```bash
curl -X DELETE "https://api.sautikit.com/v1/numbers/{id}" \
  -H "Authorization: Bearer $SAUTIKIT_API_KEY"
```

Once none remain, the trunk can be disconnected:

```bash
curl -X DELETE "https://api.sautikit.com/v1/sip-trunk" \
  -H "Authorization: Bearer $SAUTIKIT_API_KEY"
```

`GET /v1/numbers` shows which numbers are still assigned before you start releasing them.

## Example response

```json
{
  "error": {
    "code": "sip_trunk.in_use",
    "message": "remove the numbers on this trunk before disconnecting it",
    "request_id": "req_01900000abc"
  }
}
```

## Next steps

- [Numbers concepts — bring your own SIP trunk](/developers/concepts/numbers#bring-your-own-sip-trunk)
- [Numbers API](/developers/api#numbers) — release a number