I am trying to implement call forwarding using the Transfer Call tool, using a Twilio number. When I Talk to Assistent from the dashboard, Assistant says it's transferring the call, but ends the meeting and shows the error on the dashboard (image attached). This is json of my Transfer Call tool { "id": "03f12193-c4e4-4357-a1c6-06fb77fccbb3", "createdAt": "2025-05-06T11:14:42.038Z", "updatedAt": "2025-05-06T11:46:40.153Z", "type": "transferCall", "function": { "name": "transferCall", "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.", "parameters": { "type": "object", "properties": { "destination": { "description": "The destination to transfer the call A.", "type": "string", "enum": [ "+923177506776" ] } }, "required": [ "destination" ] } }, "messages": [ { "type": "request-start", "content": "I am forwarding your call to Department A. Please stay on the line.", "blocking": false, "conditions": [ { "param": "destination", "value": "+923177506776", "operator": "eq" } ] } ], "orgId": "e935ad56-c00a-461f-8aaf-3bbcb30e37e2", "destinations": [ { "type": "number", "number": "+923177506776", "message": "I am forwarding your call to Department A. Please stay on the line.", "transferPlan": { "mode": "blind-transfer", "sipVerb": "refer" }, "numberE164CheckEnabled": true } ] } https://cdn.discordapp.com/attachments/1369293753637929031/1369293753789186198/Screenshot_2025-05-06_at_5.40.34_PM.png?ex=681b55af&is=681a042f&hm=61aa0a59d6bc9c4a057ad35fed7b26ffb2f6f5821e32d83792f7d1e38755f702&

Try changing your

sipVerb

setting from "refer" to "bye" in your Transfer Call tool configuration:

json
"transferPlan": {
  "mode": "blind-transfer",
  "sipVerb": "bye"  // Changed from "refer" to "bye"
}

This may resolve the issue as some providers (including Telnyx) have suggested eliminating SIP REFER for successful call transfers. Source: - [Discord discussion about Telnyx compatibility](https://discord.com/channels/1211482211119796234/1343963959421829172)

how can i edit this json? moreover i have deleted the tool and created again using postman and now it is. { "id": "4161a76f-90fd-4303-9d49-2060f97d0a73", "createdAt": "2025-05-06T12:59:21.220Z", "updatedAt": "2025-05-06T12:59:21.220Z", "type": "transferCall", "function": { "name": "transferCall", "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.", "parameters": { "type": "object", "properties": { "destination": { "description": "The destination to transfer the call to.", "type": "string", "enum": [ "+923177506776" ] } }, "required": [ "destination" ] } }, "messages": [ { "type": "request-start", "content": "I am forwarding your call to Department A. Please stay on the line.", "conditions": [ { "param": "destination", "value": "+923177506776", "operator": "eq" } ] } ], "orgId": "e935ad56-c00a-461f-8aaf-3bbcb30e37e2", "destinations": [ { "type": "number", "number": "+923177506776", "message": "I am forwarding your call to Department A. Please stay on the line." } ] }

Cc: @Shubham Bajaj

@Haider is the Twilio number from your own personal account, or assigned by VAPI? calling Pakistan costs $0.155 per minute on Twilio, it may be blocked from usage.

Yes, the Twilio number is from my own personal account and has credit also.

it sounds to me like a limitation inside Twilio, preventing you from dialing mutiple calls at the same time, or potentially, preventing a looped call. If you want, I'll be happy to sit down and investigate this with you. This is an interesting problem. Please DM me in order to schedule this.

Hey Haider, checking if this is resolved/solved for you?