Hello, I am having an issue with my transfercall tool. In the log it says assistant forwarded the call but the transfer failed and the call ended. I use a sip trunk to do my outband calls and it's working fine the only thing that is not working is the transfercall. Here is the transfercall tool that i use : { "type": "transferCall", "destinations": [ { "type": "number", "number": "+33.......", "message": "Transfert de l'appel en cours vers le numéro +33....... Veuillez patienter." } ], "function": { "name": "transferCallTeliacomTest-14fev-MOBILE", "description": "Transfert de l appel lorsque l'utilisateur le demande.", "parameters": { "type": "object", "properties": { "destination": { "type": "string", "enum": [ "+33........" ], "description": "Transfert de l appel lorsque l'utilisateur le demande." } }, "required": [ "destination" ] } }, "messages": [ { "type": "request-start", "content": "Transfert de l'appel en cours vers le numéro +33........ Veuillez patienter.", "conditions": [ { "param": "destination", "operator": "eq", "value": "+33........" } ] } ] } Here is the call id : 512acbb0-ead8-4a27-a308-b0552fc45e41 Your help would be appreciated !

The logs clearly show successful execution and forwarding. Refer‐To is indeed present, so that is not the issue. What’s missing is unknown, can you check with your provider what's missing and why they treat the call as foreign traffic or not honor the forward.

Hello i checked with the voip provider. They tell me that the initial call goes through the Voip trunk, but that the transfer doesn't go through the same trunk. Does Vapi initiate the transfer via this same trunk ?

Yes Vapi initates the transfer from the Voip trunk provided/registered by you. What else did they say to help debug it?

they just said that they see the log with the “refer to” but that the transfer should be done via the same trunk that was initially created on vapi with the credentials of the VoiP

Hey by default and logic we do the transfer using the credentials created by you and we don't make any changes to it. This was also discussed over DMs. Now for benefit of your doubt could you elaborate more on this with example "they just said that they see the log with the “refer to” but that the transfer should be done via the same trunk that was initially created on vapi with the credentials of the VoiP"?

in fact, the voip provider tells me that they see the Refer to pointing to the right target phone number, but that this transfer would not be made on the same initial trunk because they don't manage the transfer (so it's up to vapi to redirect properly), they just give the phone line.

Your provider is indicating that they only provide the "pipe" (trunk) and won't handle any transfer logic. Vapi needs to ensure that transfer requests maintain the same authentication and routing as the original call. I have a few questions regarding your provider's requirements: 1\. Are there any specific headers that need to be preserved during transfers? 2\. Are there any special routing requirements? I'd like to clarify what they mean by "using the same authentication and routing as the original call." Based on my understanding, they likely require: \- Generating REFER requests that include: - Original trunk identity - Same authentication context - Maintained routing path through the same trunk - Required headers from the original call However, I want to confirm these requirements and gather all necessary details before submitting any feature requests to the team.

@willinabus a gentle reminder to continue this thread.

Hello sorry for my late response

Marking this ticket as Solved ✅

@willinabus tu as réussi a résoudre ? je trouve aucune solution pour qu'il arrete de raccrocher quand je demande de transferer (j'utilise Telnyx)