# 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)