Hi VAPI team, I am using your AI outbound calling system connected to my Telnyx number. I want to configure the system so that if a customer calls back after missing my outbound AI call, their callback is automatically forwarded to my personal phone number. Could you please guide me on how to set up this callback forwarding or fallback number within your system? I've tried the transfer call tool, in the logs it says: "An error occurred in this call: unknown-error". I've tried the fallback destination. Nothing happened. I really hope you can help me.

To forward inbound calls (callbacks) to your personal number, ensure your Telnyx SIP trunk has SIP REFER enabled. Then, configure your Vapi assistant with a

transferCall

tool like this:

json
{
  "type": "transferCall",
  "destinations": [
    {
      "type": "number",
      "number": "+1234567890", // your personal number in E.164 format
      "message": "Connecting you now."
    }
  ],
  "function": {
    "name": "transferCall",
    "parameters": {
      "type": "object",
      "properties": {
        "destination": {
          "type": "string",
          "enum": ["+1234567890"],
          "description": "The destination to transfer the call to."
        }
      },
      "required": ["destination"]
    }
  }
}

Tip: If you see "unknown-error" in logs, double-check that SIP REFER is enabled in your Telnyx trunk settings. Sources: - [Vapi call forwarding documentation](https://docs.vapi.ai/call-forwarding) - [Telnyx SIP integration](https://docs.vapi.ai/advanced/sip/telnyx) - [Discord troubleshooting thread](https://discord.com/channels/1211482211119796234/1343963959421829172)

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!