Ended Reason: call.in-progress.error-transfer-failed Status: queued I'm using a dynamic transient setup which previously has worked fine like this. This is the function setup: { "type": "transferCall", "destinations": [ { "type": "number", "number": "{{19.

20

}}", "callerId": "{{decodeURL("%7B%7Bcustomer.number%7D%7D")}}", "message": "One moment. Please stay on the line." } ] } The assistant is saying the message, but then the call never rings like it used to and so the forwarding never actually gets pushed through. I'm looking through the vapi logs and not really finding anything. Tried removing the callerId and message and hard coding the phone number in and it still didn't work. The phone number that the calls are forwarding to are fully functional - have continued to test and verify. Have also tested in other organizations and getting the same issue. OrgId: - 2955326d-c7db-412f-aeed-c89b1cc1ef21 Call IDs: - 019a2b8f-50a1-7dd6-8a87-6f599d85c3c9 - 019a2b7f-6bce-7ffa-8a8b-6763bea20add - 019a2b75-6f04-7cc4-89bc-5302439c31d8 - 019a2b70-d2d0-7bbc-971f-80acc7a2dc6a - 019a2b64-590a-733d-abd6-efb3cb6d28ab - 019a2894-2f6e-7889-9975-b85185b6595f

Thanks for sharing the details. To help narrow down the cause of the transferCall error, could you confirm if your assistant's configuration has

serverMessages

set to include

"phone-call-control"

or if

phoneCallProviderBypassEnabled

is set to

true

? These settings can prevent Vapi from managing transfers and are a common source of this issue ([see troubleshooting guide](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops)). If you're unsure, you can check your assistant's JSON config for these fields. Let me know what you find! Source: - [Debug call forwarding drops](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops)

is this a new feature requirement because it worked fine prior @Vapi Support Bot

If your transferCall setup worked previously but now fails, check if your assistant's configuration has

serverMessages

set to include

"phone-call-control"

or if

phoneCallProviderBypassEnabled

is set to

true

. These settings can prevent Vapi from managing transfers and are a common source of this error. This requirement is documented in the [Vapi troubleshooting guide](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops). Action: Review your assistant's JSON config and ensure:

json
"serverMessages": ["phone-call-control"],
"phoneCallProviderBypassEnabled": false

If either setting is incorrect, update it and test your transfer again. Source: - [Debug call forwarding drops](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops)

check pm

Hi Zack Siegel, To address issues with call transfers: 1. Verify the call forwarding initiation with Vapi by checking the

endedReason

field. Ensure it shows

"assistant-forwarded-call"

. If different, review and adjust your assistant configuration. 2. If the

endedReason

is

"assistant-forwarded-call"

but still drops, examine telephony provider logs for transfer errors using the

phoneCallProviderId

from the call object. Check Twilio, Vonage, or Telnyx logs, depending on your provider. 3. For SIP calls, download and analyze the packet capture using Wireshark to check for SIP

REFER

packets. Detailed guidance on resolving these issues can be found in the [troubleshooting guide](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops). For assistant-based warm transfers, ensure your configuration matches the guidelines [here](https://docs.vapi.ai/calls/assistant-based-warm-transfer), focusing on properties like

firstMessageMode

and

maxDurationSeconds

. Let me know if you need further clarification or have other questions.

The endedReason is "call.in-progress.error-transfer-failed" @Vapi Support Bot @Vapi

To help resolve your transferCall error: Can you confirm if your assistant's JSON config currently has

"serverMessages": ["phone-call-control"]

and

"phoneCallProviderBypassEnabled": false

? This is the most common cause for the

call.in-progress.error-transfer-failed

issue ([see troubleshooting guide](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops)). Source: - [Debug call forwarding drops](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops)

@Vapi Support Bot you're saying that i want phone-call-control included in the api call and phonecallproviderbypassenabled? neither of those are in the api call. not sure if they have default settings and that documentation doesn't mention this ended call reason

To resolve the

call.in-progress.error-transfer-failed

issue, explicitly set these fields in your assistant's JSON config:

json
"serverMessages": ["phone-call-control"],
"phoneCallProviderBypassEnabled": false

Add or update these properties, then test your transfer again. This is the most common fix for your error according to the [Vapi troubleshooting guide](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops). Source: - [Debug call forwarding drops](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops)

where should they be branched under @Vapi Support Bot

You should add

"serverMessages"

and

"phoneCallProviderBypassEnabled"

as top-level fields inside your assistant's main JSON object. For example:

json
{
  "name": "Your Assistant Name",
  "serverMessages": ["phone-call-control"],
  "phoneCallProviderBypassEnabled": false,
  // ...other assistant properties...
}

If your config is nested or managed differently, could you share a snippet of your assistant JSON structure? That will help me give you the exact placement. Source: - [Debug call forwarding drops](https://docs.vapi.ai/phone-calling/transfer-calls/debug-forwarding-drops)

I'm getting a 400 error message now that: property serverMessages should not exist attached is the json for the api call: @User https://cdn.discordapp.com/attachments/1432762994294657106/1433452846703186042/message.txt?ex=6904be7e&is=69036cfe&hm=41a935420a221ba699676f7be2c548ef02daefcc401f267af36282e08121ed5d&

Thank you for providing this information. We’ll be looking into it further to better understand the situation and determine the next steps. Our team will update you as soon as we have more details, and we truly appreciate your patience and cooperation in the meantime.

Thanks. Any update? @Vapi Support Bot

Thanks for getting back to us and updating us We’ll share an update as soon as more information becomes available. We appreciate your understanding and patience as we continue our investigation.

Any update? @Vapi Support Bot