Hi, I'm trying to send voicemail messages via my call assistant, but I'm seeing every call I make to my Twilio number (trial account) end with the customer-did-not-answer reason. The call is successfully made to my Twilio number as expected BUT if the call goes to voicemail, my configured voicemail message is never left and the call ends with ends a customer-did-not-answer reason I've created my Twilio number following https://docs.vapi.ai/phone-numbers/import-twilio - NOTE: I am currently on a Twilio trial account I'm not seeing errors in my Twilio call logs btw vapi call ids with the issue: - 019a8ea2-f444-7440-b8f7-474ff88798ff - 019a8e29-974f-755f-8b4e-2c4f32c9b829 - 019a8376-908e-7110-be4d-626517d3f2ab - 019a8369-d921-7cce-ba7b-931bee33e2bc I am using the vapi sdk to make these calls:

import { VapiClient } from '@vapi-ai/server-sdk';
// Create VapiClient instance
const vapi = new VapiClient({ token: vapiApiKey });

// Create call using SDK
const callData = await vapi.calls.create({
  assistant: body.assistant,
  phoneNumberId: body.phoneNumberId,
  customer: body.customer,
  name: body.name,
});

Here is an example transient assistant config I atach to the call with:

{
  "model": {
    "model": "gpt-4o",
    "tools": [
      {
        "type": "voicemail",
        "function": {
          "name": "leave_voicemail",
          "description": "Leave a voicemail message when you detect you've reached a voicemail system"
        },
        "messages": [
          {
            "type": "request-start",
            "content": "Hey {redacted}. This is {redacted}, CEO at {redacted}. Call me back if you're interested in increasing sales win rates at {redacted}."
          }
        ],
        "beepDetectionEnabled": false
      }
    ],
    "messages": [
      {
        "role": "system",
        "content": "You are a sales representative for {redacted}.\nIf at any point you determine you're speaking to a voicemail system\n(greeting mentions 'unavailable', 'leave a message', 'voicemail', 'at the tone', 'beep', etc.),\nwait for the voicemail message to end and then use the leave_voicemail tool."
      }
    ],
    "provider": "openai",
    "maxTokens": 5000,
    "temperature": 0.3,
    "knowledgeBase": {
      "topK": 1,
      "fileIds": [],
      "provider": "canonical"
    },
    "emotionRecognitionEnabled": false
  },
  "voice": {
    "voiceId": "uju3wxzG5OhpWcoi3SMy",
    "provider": "11labs",
    "chunkPlan": {
      "enabled": true,
      "formatPlan": {
        "enabled": true,
        "numberToDigitsCutoff": 2025
      },
      "minCharacters": 15,
      "punctuationBoundaries": [
        ".",
        "!",
        "?",
        ";",
        ",",
        ":"
      ]
    },
    "fillerInjectionEnabled": false
  },
  "firstMessage": "",
  "firstMessageInterruptionsEnabled": true,
  "firstMessageMode": "assistant-waits-for-user",
  "voicemailDetection": {
    "enabled": true,
    "provider": "twilio",
    "machineDetectionTimeout": 45,
    "voicemailDetectionTypes": [
      "machine_end_beep",
      "machine_end_silence",
      "machine_end_other"
    ],
    "machineDetectionSilenceTimeout": 6000,
    "machineDetectionSpeechThreshold": 2500,
    "machineDetectionSpeechEndThreshold": 2500
  },
  "voicemailMessage": Hey {redacted}. This is {redacted}, CEO at {redacted}. Call me back if you're interested in increasing sales win rates at {redacted}.",
...
}

Can I please get some help troubleshooting the cause of this? Thanks in advance

Hi there, Thank you for your message. Our team is currently out of the office. We operate Monday through Friday, from 9:00 AM to 8:00 PM Pacific Standard Time (PST). We’ll get back to you as soon as possible during our normal business hours. If your message is urgent, please mark it accordingly or include “URGENT” in the subject line, and we’ll do our best to respond promptly. Warm regards, Vapi Customer Support Team

Could I get some help on this please. None of my outbound calls are working

Hi certified dirtiboi, We’re sorry for the inconvenience and are more than happy to help if there’s anything else you need.

Thanks. Now that I have voicemail messages working, I have another question. Is it possible to send ringless voicemails to a number using vapi and/or twilio?

No it is not possible with Twilio