13211: Dial: Invalid ifMachine value

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.

• 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.

• 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.

• TwiML Voice: <Dial>
• TwiML Voice: <Number>
• Answering Machine Detection