---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/13239#article
headline: "13239: Dial->Conference: Invalid Trim Value"
url: https://www.twilio.com/docs/api/errors/13239
inLanguage: en
dateModified: 2026-03-11T18:38:39.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 13239: Dial->Conference: Invalid Trim Value

Log Level: ERROR

## Description

Twilio returns this error when the `<Conference>` noun receives an invalid `trim` value. The documented `trim` values for `<Conference>` are `trim-silence` and `do-not-trim`.

### Possible causes

* The `<Conference>` noun includes a `trim` attribute with a value other than `trim-silence` or `do-not-trim`.

### Possible solutions

* Update the `<Conference>` noun so `trim` is set to `trim-silence` or `do-not-trim`.
* Remove the `trim` attribute if you want Twilio to use the documented default value of `trim-silence`.

## Additional resources

* [TwiML Voice: `<Conference>`](/docs/voice/twiml/conference)