---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/13211#article
headline: "13211: Dial: Invalid ifMachine value"
url: https://www.twilio.com/docs/api/errors/13211
inLanguage: en
dateModified: 2026-06-08T11:29:20.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 13211: Dial: Invalid ifMachine value

Log Level: WARNING

## Description

Twilio returns this warning when you set the `<Dial>` `ifMachine` value to anything other than `hangup`, `continue`, or `false`. Use `ifMachine` only with one of those supported values when you want call handling to change based on whether a machine answers.

### Possible causes

* You set `ifMachine` to a value outside the allowed set of `hangup`, `continue`, or `false`.
* You passed a machine detection value intended for a different Voice parameter, such as `Enable` or `DetectMessageEnd`, instead of a supported `ifMachine` value.

### Possible solutions

* Update the `ifMachine` value in your `<Dial>` TwiML to `hangup`, `continue`, or `false`.
* If you need answering machine detection for an outbound call flow, use the supported machine detection settings for the API surface you are using. Use `MachineDetection` on the Calls API or `machineDetection` on `<Dial><Number>` where supported.
* Review the TwiML or API request that creates the outbound leg and make sure the parameter name matches the feature you are using. TwiML verb and attribute names are case sensitive.

#### Additional resources

* [TwiML Voice: `<Dial>`](/docs/voice/twiml/dial)
* [TwiML Voice: `<Number>`](/docs/voice/twiml/number)
* [Answering Machine Detection](/docs/voice/answering-machine-detection)