Hello, I'm testing a new agent and the transfer call is not working every time. Example: call_id: cd1d36e0-e2e6-42a3-8ed7-1694e49ad647 - no transfer call_id: de574300-a9b9-4230-8c4b-f3fd1fb288cf - transfer success Is there any issue on your side? Thank you!

Hi there! 👋 I'm unable to check if there's a specific issue on our side with those particular call IDs, but I can definitely help troubleshoot why your transfer call function isn't working consistently. Based on the information I've found, there are several common reasons why the Transfer Call function might work intermittently: ### Common Causes for Inconsistent Transfer Call Behavior 1. **Server Event Configuration**: If you have the "phone-call-control" server event enabled in your assistant, this can prevent Vapi from handling call transfers properly. [Removing this event](https://discord.com/channels/1211482211119796234/1211483291191083018/threads/1335869152535121960) often resolves transfer issues. 2. **Forwarding Phone Number Format**: The

forwardingPhoneNumber

might be incorrectly formatted or invalid. Ensure it's in the correct E.164 format (e.g., +15558675309) or try setting it to null/empty string to see if that helps. 3. **SIP REFER Handling**: If you're using a SIP system, there might be issues with how it handles SIP REFER messages, which Vapi uses for transfers. 4. **Model Behavior**: The model might occasionally speak the VAPI tool call code instead of executing it (happens in approximately 20% of cases according to [user reports](https://discord.com/channels/1211482211119796234/1211483291191083018/threads/1331648945818177586)). 5. **Destination Number Issues**: Transfers can fail if the destination number is busy, out of reach, or if there are international calling restrictions. ### Debugging Steps To troubleshoot this issue: 1. Review call logs for the failed transfer attempts to identify any error patterns 2. Check your assistant configuration, particularly if you have the "phone-call-control" server event enabled 3. Verify the format of your forwarding phone numbers 4. Test with different models - some users report that switching to GPT4o makes transfers more consistent

it works completely randomly, I couldn't find a pattern. all the settings are the same

Hey! To help track down this issue, could you share: - When exactly this happened (the timestamp) - What response you actually got instead for no transfer This would really help us figure out what went wrong!

Hi @Shubham Bajaj . In my first post there are 2 call ids, one with a working transfer and one with a failed transfer. In case of a failed transfer nothing happens, call is ending in 5 seconds after the agent confirm the transfer. This issues is random.

🔵 11:28:05:538 Found Phone Number Destination. Destination: { "type": "number", "number": "100001", "message": "Te voi transfera către colegii de la suport tehnic. îți mulțumesc!", "description": "Transferă apelul către Suport Tehnic atunci cand clientul are probleme de functionare a serviciilor.", "numberE164CheckEnabled": false, "callerId": "", "transferPlan": { "mode": "blind-transfer", "message": "Te voi transfera către colegii de la suport tehnic. îți mulțumesc!", "sipVerb": "refer" } } "id": "cd1d36e0-e2e6-42a3-8ed7-1694e49ad647" 🔵 11:28:05:563 Live Call Manager Ending...(assistant-forwarded-call) The call was forwarded successfully, but the destination which your assistant passed might be incorrect, which eventually resulted in failure. That's why you felt like "the call was not transferred".