My Vapi AI Agent will speak to the prospect, qualify them, announce that the ai agent will transfer the call after seeing that the prospect is a good fit for the program, then it will just hang up the call without transferring the prospect. The call status shows that the agent initiated/completed the transfer but also shows that the ai agent forwarded the call. But neither scenario actually happened. Please assist.

Thank you for describing the issue. To help diagnose the problem, could you please confirm which transfer mode (e.g., "blind transfer", "warm-transfer-with-summary", "warm-transfer-experimental", etc.) and telephony provider (e.g., Twilio, SIP trunk, etc.) you are using in your Vapi agent's transferCall configuration? Sources: - [Vapi documentation: call forwarding](https://docs.vapi.ai/call-forwarding) - [Vapi documentation: assistant-based warm transfer](https://docs.vapi.ai/calls/assistant-based-warm-transfer) - [Vapi documentation: dynamic call transfers](https://docs.vapi.ai/calls/call-dynamic-transfers) - [Discord: SIP trunking and transfer troubleshooting](https://discord.com/channels/1211482211119796234/1372460612499804270)

Blind transfer

Hi Billions14, To troubleshoot the issue of calls dropping immediately after initiating a transfer, please follow these steps: 1. **Verify Forwarding Initiation**: Check if Vapi has successfully initiated the call forwarding by using the Vapi API. Use one of the methods outlined for different SDKs, such as:

bash
   curl -X GET "https://api.vapi.ai/call/{call_id}" \
   -H "Authorization: Bearer YOUR_API_KEY" \
   -H "Content-Type: application/json"

or via the TypeScript/Python SDK. 2. Analyze the `endedReason`: - A response of

"assistant-forwarded-call"

indicates successful forwarding initiation, allowing you to move to the next steps. - Any other

endedReason

suggests configuration issues. Review your assistant settings to ensure

"phone-call-control"

is not in

serverMessages

if you aren't handling call control. 3. **Check Telephony Provider Logs**: If Vapi forwarded successfully but the call still drops: - Retrieve the

phoneCallProviderId

from the call object. - Check your telephony provider's call logs using this ID to find any transfer errors or execution issues. 4. **SIP Call Analysis**: If using SIP, download and analyze the SIP packet capture. Look for the

REFER

packet to confirm if the transfer request was sent to your provider. 5. **Configuration Checks**: - Verify the destination number format and ensure it is correct. - Ensure

phoneCallProviderBypassEnabled

is set to

false

for transfers managed by Vapi. For more detailed analysis and solutions, you can refer to the [debugging guide](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops).