We are currently facing an issue with the call transfer functionality. The transfer is not working as expected during live calls. The call gets disconnected immediately after the transfer call tool is executed. Below are the details for reference: Assistant ID: a973fa47-6c8a-48cb-909b-5127dee13224 Phone Number ID: 728726d6-8a17-41d5-87e7-0ab26b74098a Call ID: 019e1c96-6873-7000-95bf-3d339e261bff Tool ID: a53d6677-6edd-4569-bd59-14b102120636 Transfer Number: +918770821586 Issue Description: The call transfer action gets triggered, but the call is not being transferred successfully. Please help us identify the cause and suggest a resolution.

Since this is on Vapi, the issue is most likely related to the transfer tool configuration, Twilio/SIP settings, or the destination number not being accepted during the handoff. In many cases, Vapi executes the transfer tool correctly but the provider drops the call because the transfer bridge fails. I can help you debug it. Are you using Twilio or a custom SIP provider for the phone number connected to Vapi?

I'm using twillio

Same issue here using Vapi default provider

Perfect, that helps. I’ll help you check the Vapi transfer tool setup, Twilio call logs, and SIP transfer behavior to find exactly why the call drops after transfer. Usually it’s a Twilio transfer permission or bridge configuration issue, and it’s fixable pretty quickly.

ok guide me how to fix it

I can guide you through call or I should just craft out a step-by-step guide...either way you want it

craft out a step-by-step guide

Alright can we connect @Adarsh_dev

yes sure

Hi Adarsh, Please try calling the destination number directly first to make sure it is reachable and able to receive calls normally. I’d also recommend simplifying the current transfer setup for testing, since it is currently using warm-transfer-wait-for-operator-to-speak-first-and-then-say-message with sipVerb: "refer". trying a simpler transfer setup can help check whether the problem is caused by the current transfer configuration or by the destination number after the call is forwarded. here are the docs reference: https://docs.vapi.ai/call-forwarding https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops Best, Akash Customer Support Vapi