I'm using this with my custom LLM. So far, the transfer and all happens well. However, if the number to which the conversation is being transferred declines the call, or doesn't pick up, the fallback does not seem to work. This is what my config looks like when sent to the conversation's control URL { "type": "transfer", "destination": { "type": "number", "number": phone_number, "callerId": '{{phoneNumber.number}}', "transferPlan": { "mode": "warm-transfer-experimental", "holdAudioUrl": "https://file.mp3", "summaryPlan": { "enabled": True, "messages": [ { "role": "system", "content": "Please provide a summary of the call." }, { "role": "user", "content": "Here is the transcript:\n\n{{transcript}}\n\n" } ] }, "fallbackPlan": { "message": "It seems the person is currently busy or on another call. Can I take a message?", "endCallEnabled": False } } } } CC: @Prashant Abbi

Suggestion: Double-check that your

fallbackPlan

is nested directly inside the

transferPlan

and that your transfer mode is

"warm-transfer-experimental"

. Also, ensure you are using a Twilio phone number, as this mode only works with Twilio. Here’s a sample structure for reference:

json
"transferPlan": {
  "mode": "warm-transfer-experimental",
  "holdAudioUrl": "https://file.mp3",
  "summaryPlan": { ... },
  "fallbackPlan": {
    "message": "It seems the person is currently busy or on another call. Can I take a message?",
    "endCallEnabled": false
  }
}

If the fallback still does not trigger, review your assistant/server configuration for overrides or conflicting settings. See more in the [Vapi documentation](https://docs.vapi.ai/call-forwarding). Source: - [Call Forwarding](https://docs.vapi.ai/call-forwarding)