---
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"@id": https://www.twilio.com/docs/api/errors/17511#article
headline: "17511: Invalid audioChannelIndex. Must be 1 or 2"
url: https://www.twilio.com/docs/api/errors/17511
inLanguage: en
dateModified: 2026-07-31T15:59:35.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 17511: Invalid audioChannelIndex. Must be 1 or 2

Log Type: APPLICATION

Log Level: WARNING

## Description

Twilio could not create a new transcription because a participant's `audioChannelIndex` value is outside the valid range.

### Possible causes

The `audioChannelIndex` is 0, negative, or greater than 2.

### Possible solutions

Set `audioChannelIndex` to 1 or 2 for each participant.

#### Additional resources

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