---
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headline: "17510: Invalid participant count"
url: https://www.twilio.com/docs/api/errors/17510
inLanguage: en
dateModified: 2026-07-31T15:59:35.000Z
author:
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  name: Twilio Developer Education Team
publisher:
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  name: Twilio
---

# 17510: Invalid participant count

Log Type: APPLICATION

Log Level: WARNING

## Description

Twilio could not create the transcription because the participant count is invalid.

* If the request specifies `sourceId`, you can provide either 0 or 2 participants.
* If the request specifies `mediaUrl` together with a Conversation configuration, you must provide exactly 2 participants.

### Possible causes

* Supplying only 1 participant
* Supplying more than 2 participants

### Possible solutions

* For `mediaUrl` requests that use a Conversation configuration, provide exactly 2 participants—one per audio channel.
* For `sourceId` requests, either omit the `participants` array or provide exactly 2 participants.

#### Additional resources

* [Specify participant information](https://www.twilio.com/docs/voice/api/batch-transcription-resource#specify-participant-information)