Hi Vapi Support, transferCall tool executes successfully but call ends immediately instead of transferring. Issue: - Tool creation: ✅ Successful (201 Created) - AI triggers tool: ✅ Successful - AI speaks message: ✅ Successful - Transfer: ❌ FAILS - Call ends immediately - Destination never rings: ❌ Tested Methods: 1. Number transfer:

+90XXXXXXXXXX

2. SIP transfer:

sip:XXXXXXXXXX@sip.netgsm.com.tr

Both methods fail with same behavior. Environment: - Agent ID:

56d1a0eb-eb0c-49f7-a762-125ff3106de1

- Phone ID:

e5fa5e02-daf3-4df5-a8f5-b854db178feb

- Failed Call ID: 0199da09-1821-7dd9-8245-b138f0bbb386 0199da07-7986-766e-9120-c4ae2675384b 0199d9f4-e7e8-7888-acb4-ee20abcb8ab7 - Provider: NetGSM (Turkey) - Language: Turkish Expected: Call transfers to destination after AI message Actual: Call ends immediately after AI message Questions: 1. Any Turkey-specific transfer requirements? 2. Need forwardingPhoneNumbers in agent config? 3. Can you check my call logs for transfer failure reason? Thanks!

Hi there, Thank you for your message. Our team is currently out of the office. We operate Monday through Friday, from 9:00 AM to 8:00 PM Pacific Standard Time (PST). We’ll get back to you as soon as possible during our normal business hours. If your message is urgent, please mark it accordingly or include “URGENT” in the subject line, and we’ll do our best to respond promptly. Warm regards, Vapi Customer Support Team

Same problem here

I could assist you in solving this, let me know when you’d chanced for a quick chat..

Warm Call forwarding is only supported on twillio at the moment

Turkey is highly regulated. Sending calls from Turkey to a remote server is possible. Sending calls to Turkey, from a non-turkey IP is most probably blocked by your carrier. Feel free to DM me and I'll explain how to resolve this.

Hi Burak, To troubleshoot issues with call forwarding dropping immediately after initiation, follow these steps: 1. **Verify Forwarding Initiation**: Check if Vapi successfully initiated the forwarding. - Use the API to fetch the call details and look for

"endedReason": "assistant-forwarded-call"

. If not present, verify your configuration. 2. **Configuration Check**: Ensure your

serverMessages

does not include

"phone-call-control"

. If present, it's overriding Vapi's control. 3. **Telephony Provider Logs**: If the call was marked as forwarded but still drops, check your telephony provider's logs using the

phoneCallProviderId

for errors in their dashboard. 4. **SIP Analysis (if applicable)**: Download the PCAP file and use Wireshark to check for SIP transfer packets. Look for REFER packets and responses. 5. **Common Solutions**: - Verify the destination number format is correct and reachable. - Ensure

phoneCallProviderBypassEnabled

is set to

false

unless custom call control is implemented. For detailed steps, see the [Debug call forwarding drops guide](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops).