URGENT Issue: assistant-request Webhook Not Firing...
# supportb
bongo4200.
08/31/2025, 7:07 AMHello Vapi Support Team,
I'm opening a new ticket for a critical issue I'm facing with dynamic variables on my telephony agent.
What's Working: Thanks to previous help, my Twilio BYO numbers are now successfully connecting to my Vapi agent via the /inbound_call webhook. The agent answers the call correctly.
> The Problem: The initial assistant-request webhook is not being sent from Vapi to my backend on Make.com.
> The Result: Because the webhook never fires, my Make.com scenario (which looks up business details) never runs. This causes the agent to speak the literal variable names (e.g., it says "{business_name}") instead of the dynamic data.
> What I've Checked:
> * I have confirmed there are no new execution logs in my Make.com scenario when a call comes in, which proves the webhook is not being sent from Vapi.
> * The webhook URL for my Make.com scenario is correctly configured in my agent's Advanced > Messaging > Server URL field.
> * The web-based "Talk to Assistant" feature does correctly fire this webhook, but telephony calls do not.
> Could you please investigate why the assistant-request webhook is not being triggered for inbound telephony calls on my account? It seems to be the final piece needed to get my system working.
> Assistant ID: 76f3b9f6-6324-4861-bfc5-5e4bef85f41b
> Thank you for your help.
>
c
Chiranjeet Mishra
08/31/2025, 7:07 AMHi 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
b
bongo4200.
09/01/2025, 3:34 AM@User please help me resolve this issue, thank you!
c
Chiranjeet Mishra
09/03/2025, 6:54 AMPlease remove the assistantId from the call request. Once you remove it, it will force the API to fetch the assistant with the assistant-request webhook.
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bongo4200.
09/08/2025, 12:06 AM@Vapi I have removed the assistant from my phone numbers but now when I call i just hear and automated message saying: "couldn't get assistant"
bongo4200.
09/08/2025, 12:14 AMDo I need to add my assistant ID to my vapi inbound webhook on twillio? Or what would the solution be? Happy to provide any further information. Thanks.
bongo4200.
09/08/2025, 11:33 PMHello,
Thank you for your previous advice. I am writing to report that I have followed your instructions exactly, but the system is still failing with a critical error.
Here is a summary of the steps I have taken based on your guidance:
I have confirmed that no assistant is assigned to my phone number in the Vapi dashboard's "Inbound Settings".
My Tradie Agent (Main) has its Server URL (Advanced > Messaging) correctly pointing to my Make.com webhook.
My Make.com scenario is correctly configured to listen for the assistant-request and respond with the required JSON, including the correct assistantId and the override.variableValues.
The Result: When I call my Twilio number now, the call connects, but I hear an automated Vapi error message that says: "Couldn't Get Assistant. Either Set The Assistant I D On The Phone Number. Or, To Debug Your Assistant Request, Check The Debugging Artifacts That Were Just Sent To Your Server."
I have checked my Make.com scenario logs immediately after the call, and it confirms that no request was received from Vapi. The scenario was not triggered.
Conclusion: This definitively proves that even with the assistant un-assigned, Vapi's platform is failing to send the assistant-request webhook to the Server URL configured in my agent's settings. Because the webhook never fires, my backend cannot provide the assistantId, and the system fails.
We have now tried every possible user-side configuration. This appears to be a platform-level bug. Could you please escalate this to an engineer to investigate why the assistant-request webhook is not being sent for my account's telephony calls?
Here are the details for the latest failed call:
Vapi Assistant ID: r0OD73nMrg74ALdXpHu8
Twilio Phone Number: +6498867324
Failed Twilio Call SID: CA18672cbd82973b30238fde4bd07a1d2e
Thank you for your urgent attention to this matter.
bongo4200.
09/08/2025, 11:54 PM@User
c
Chiranjeet Mishra
09/10/2025, 7:08 AMThank you for providing that information. We will review the details and get back to you shortly with an update
Chiranjeet Mishra
09/15/2025, 5:11 PMHello,
We sincerely appreciate your understanding and apologize for the inconvenience this has caused.
Our team is currently investigating the matter to determine the root cause and implement a resolution as quickly as possible. We will provide you with updates as soon as new information becomes available, and we remain committed to ensuring this issue is fully resolved