Hello! I've encountered a problem with transfer call, it doesn't work somehow.

A common reason transfer calls don't work is a missing "destination" property in your TransferCall tool configuration. Try updating your tool's parameters as follows:

json
"parameters": {
  "type": "object",
  "properties": {
    "destination": {
      "type": "string",
      "enum": ["+1234567890"], // Replace with your external number in E.164 format
      "description": "The destination to transfer the call to."
    }
  },
  "required": ["destination"]
}

Update your configuration and test again—this should resolve most transfer call issues. For more details, see the [Vapi documentation: call forwarding](https://docs.vapi.ai/call-forwarding). Source: - [Vapi documentation: call forwarding](https://docs.vapi.ai/call-forwarding)

Hello! Thank you for the answer. i do have all the required fields. but it still donesn't initiate a call not in a Workflow and also not with an assistant { "id": "b6aa776c-2558-41d6-b7e7-3470f1eacb68", "createdAt": "2025-09-04T09:07:01.813Z", "updatedAt": "2025-10-01T12:21:29.482Z", "type": "transferCall", "function": { "name": "transferCall6", "description": "Use this function to transfer the call. Only use it when following instructions that explicitly ask you to use the transferCall function. DO NOT call this function unless you are instructed to do so." }, "messages": [ { "type": "request-start", "content": "", "blocking": false } ], "orgId": "ce6d02dc-881d-4e40-a3ef-5f865e1583c3", "destinations": [ { "type": "number", "number": "+4916090203026", "transferPlan": { "mode": "blind-transfer", "sipVerb": "refer" }, "numberE164CheckEnabled": true } ] }

Hey! To help track down this issue, could you share: \- The call ID \- When exactly this happened (the timestamp) \- What response you expected to get \- What response you actually got instead This would really help us figure out what went wrong!