---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/13230#article
headline: "13230: Dial->Conference: Invalid muted value"
url: https://www.twilio.com/docs/api/errors/13230
inLanguage: en
dateModified: 2026-06-09T11:00:42.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 13230: Dial->Conference: Invalid muted value

Log Level: WARNING

## Description

This warning occurs when the `muted` attribute on `<Conference>` is set to a value other than `true` or `false`. The `muted` attribute controls whether a participant can speak in the conference and defaults to `false`.

### Possible causes

* The `muted` attribute on `<Conference>` was set to a value other than `true` or `false`.
* Your application included `muted` in generated TwiML even though the participant did not need to join muted. When you do not set `muted`, Twilio uses the default value of `false`.
* You need to change mute state after the participant joins, but the initial `<Conference>` TwiML is being used with an unsupported `muted` value instead of a valid boolean value.

### Possible solutions

* Set the `muted` attribute on `<Conference>` to `true` or `false` only.
* If the participant should join unmuted, remove the `muted` attribute and let Twilio use the default value of `false`.
* If you need to mute or unmute a participant after they join the conference, update the participant by using the Conference Participant API.

#### Additional resources

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