---
title: "Challenge a parked inbound REGISTER with a 401 digest auth request"
method: POST
path: "/sip/registrations/attempts/{id}/challenge"
tags: ["SIP Registrations"]
---

# Challenge a parked inbound REGISTER with a 401 digest auth request

`POST /sip/registrations/attempts/{id}/challenge`

Targets an inbound REGISTER surfaced via the `sip.registration_attempt` event (by its `attempt_id`). Sends a SIP 401 with a `WWW-Authenticate` digest challenge; the UA's credentialed re-REGISTER is verified against the supplied credential and, on success, bound and answered with 200 OK. Provide either `password` or `ha1`. The attempt must still be parked (it auto-accepts after the consult timeout).

## Request body

- ChallengeRequest
  - `realm` string, required
  - `username` string
  - `password` string
  - `ha1` string
  - `algorithm` string
  - `qop` string[]
  - `max_expires` integer

## Response `202`

401 challenge queued

## Other responses

- `400` — Missing realm/credential
- `404` — Registration attempt not found or already decided

---

[API](https://skmtc.net/voiceblender/apis/voiceblender-api.md) · [All operations](https://skmtc.net/voiceblender/apis/voiceblender-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/voiceblender/voiceblender-api/revisions/a9fef0514840/schema)