---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/13235#article
headline: "13235: Dial->Conference: Invalid beep value"
url: https://www.twilio.com/docs/api/errors/13235
inLanguage: en
dateModified: 2026-06-09T11:00:42.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 13235: Dial->Conference: Invalid beep value

Log Level: WARNING

## Description

This warning occurs when you set the `<Conference>` `beep` attribute to a value Twilio does not accept. Use only `true`, `false`, `onEnter`, or `onExit` to control whether notification beeps play when participants join or leave a conference.

### Possible causes

* The `beep` attribute in your `<Dial><Conference>` TwiML was set to a value other than `true`, `false`, `onEnter`, or `onExit`.
* Your application generated the `beep` value dynamically and introduced a typo, unsupported casing, or another unsupported value. Twilio only accepts `true`, `false`, `onEnter`, or `onExit`.
* You passed an unsupported `beep` value when creating or updating a conference participant through the Conference Participant API.

### Possible solutions

* Update your `<Conference>` TwiML so `beep` uses one of the supported values: `true`, `false`, `onEnter`, or `onExit`.
* Choose the value that matches the participant experience you want. Use `true` for beeps on join and leave, `false` for no beeps, `onEnter` for join only, or `onExit` for leave only.
* If you set conference options through the Conference Participant API, send the same supported `beep` values there and review any application logic that builds the request.

#### Additional resources

* [TwiML Voice: `<Conference>`](/docs/voice/twiml/conference)
* [Voice Conference overview](/docs/voice/conference)
* [Conference Participants API](/docs/voice/api/conference-participant-resource)