via phone example: 548740fa-6f7b-47c5-b9f2-82ce0b402023 via web example: 6c624100-9f47-4f85-8327-493efafadb28 Using an AU mobile number as the destination. With the custom tool id cb032523-e163-45e4-afd1-50f192ed96ea :

{
  "id": "cb032523-e163-45e4-afd1-50f192ed96ea",
  "createdAt": "2025-03-24T05:13:00.351Z",
  "updatedAt": "2025-03-24T05:28:34.585Z",
  "type": "transferCall",
  "function": {
    "name": "transfer_call_tool",
    "strict": false,
    "description": "Transfer the call to Ben or when the user asks to speak to a human. ",
    "parameters": {
      "type": "object",
      "properties": {},
      "required": []
    }
  },
  "messages": [],
  "orgId": "b947b20e-6a50-489c-a96c-e2621da8bd3f",
  "async": false,
  "destinations": [
    {
      "type": "number",
      "number": "+614XXXXXXXX",
      "message": "Transferring you to Ben now, give me a moment. I'll also let Ben know what we were talking about.",
      "description": "When the user want's to speak to Ben",
      "transferPlan": {
        "mode": "blind-transfer",
        "message": "",
        "sipVerb": "refer",
        "summaryPlan": {
          "enabled": true,
          "timeoutSeconds": 5,
          "useAssistantLlm": false
        }
      },
      "numberE164CheckEnabled": false
    }
  ]
}

Also tried the built in transfer option in the UI. Call logs show a successful transfer, but the call just drops.

Hi there! I see you're having trouble with call transfers to an Australian mobile number. 👋 I'm unable to diagnose the exact issue with your specific AU mobile number, but I can definitely help explain why this might be happening and provide some troubleshooting steps. Based on the information I found, there are several potential reasons why your call transfers are dropping despite logs showing success: ## Potential Causes 1. **International Number Limitations**: Vapi numbers can only call US and Canada numbers. Since you're using an AU mobile number as the destination, this could be causing the call to drop after the transfer attempt. According to [documentation](https://discord.com/channels/1211482211119796234/1211483291191083018/threads/1336713212233515089), this is a known limitation. 2. **SIP Configuration Issues**: Your custom tool is using

sipVerb: "refer"

, which might be causing compatibility problems. Some systems aren't configured to handle SIP REFER messages properly, which Vapi uses for transfers. As noted in [support threads](https://discord.com/channels/1211482211119796234/1211483291191083018/threads/1333634755044048979), this is a common issue. 3. **Call Log Accuracy**: The call logs in Vapi may not always accurately reflect what's happening with the call. There are [multiple reports](https://discord.com/channels/1211482211119796234/1211483291191083018/threads/1334368749716897872) of logs showing successful transfers when the call actually drops. ## Troubleshooting Steps Here are some steps you can try: 1. **Try Different SIP Verb**: Consider modifying your custom tool to use a different SIP verb if possible. Some users have had success by switching from REFER to INVITE. 2. **Check E164 Format**: Although you've set

numberE164CheckEnabled: false

, ensure your number format is correct. The standard format should be +[country code][number].

@Ben from the Future did you get around this ? I have a been facing the same issue for an au number.

No joy so far

Looking into it.

Thanks @Shubham Bajaj ! I’ll have a look!

@Ben from the Future i don't know if this is the case with you but i found out that i cant forward to 1300 type numbers

@Raju interesting! This was to a regular mobile number +614xxxxxx

oh thats strange, it worked with regular phone numbers in my case