DTMF ISSUE USING TWILIO
# supportn
Nikki
07/09/2025, 7:41 PMOkay so guys I am trying to use DTMF using Twilio, I am using n8n for the automation process.
So, what I am doing is that I am using triggerring the n8n webhook using the twilio number. When I make call to the twilio number then it triggers the n8n flow, I have stored the DTMF responses inside the respond to webhook node in n8n as shown in the image.
So, this flow works perfectly fine, now here is the issue, I am using this flow to trigger a second flow which then compares the digits if it is one then it transfers the call to the vapi agent to which I have assigned a twilio number.
But the issue is the call gets disconnected after a few seconds without any response, and the child call on twilio shows the status as busy, adn there are no logs as well.
SO, the conclusion that I have reached is that vapi thinks that the call that is being made directly from the n8n flow is a bot and rejects it.
Note: When I make a call using my phone number to the vapi agent then it connects perfectly and works fine.
I have provided all the necessary screenshots kindly help me get through it.
Regards
https://cdn.discordapp.com/attachments/1392591484464660540/1392591484720648243/image.png?ex=68701763&is=686ec5e3&hm=d2bbe9e50aae12f8d1c45f923f2b19332425b5836fc0e25a60c8cc8e3a94f75a&
https://cdn.discordapp.com/attachments/1392591484464660540/1392591485261582347/image.png?ex=68701763&is=686ec5e3&hm=f9645e90e081804c83c055eef846a8c404fd531afa8a0a4275a766e1e9c6ea38&
https://cdn.discordapp.com/attachments/1392591484464660540/1392591485542596730/image.png?ex=68701763&is=686ec5e3&hm=6e1e56a0eccbd17ec78021dc77fcd949563339a3264e3ef754982051938185ab&
https://cdn.discordapp.com/attachments/1392591484464660540/1392591485827944608/image.png?ex=68701763&is=686ec5e3&hm=cc8590ea966ac03a0fde8d0c82ae53f5f576fca809bf2c0f31042803f0e0a765&
Nikki
07/09/2025, 7:43 PM@Kings_big💫 Kindly look into it Thanks
c
Chiranjeet Mishra
07/09/2025, 8:09 PMIt's because you’re triggering vapi with an API call instead of returning proper TwiML..
Nikki
07/09/2025, 8:16 PMinstead of adding the response tags?
k
Kings_big💫
07/09/2025, 8:18 PMYes
n
Nikki
07/09/2025, 8:20 PMSo that's what I am already doing ðŸ˜
k
Kings_big💫
07/09/2025, 8:23 PMChecking if it solved
n
Nikki
07/09/2025, 8:23 PMsure, I will try again. and will let u know
k
Kings_big💫
07/09/2025, 8:25 PMAlright
n
Nikki
07/09/2025, 8:27 PMNikki
07/09/2025, 8:27 PMNikki
07/09/2025, 8:27 PM@Kings_big💫
Nikki
07/09/2025, 8:27 PMNikki
07/09/2025, 8:28 PMNikki
07/09/2025, 10:17 PM@Kings_big💫??
k
Kings_big💫
07/10/2025, 6:28 AMSend your call_id
n
Nikki
07/10/2025, 11:28 AMthere is no call id when the call doesnt even connects brody.
Secondly I tried triggering a call through the websocket so yes I have call ids for that.
684a624d-d2b9-4ea7-9ec9-c7dc7ed50133
I was able to connect to the websocket using this but there was no response from the agent.
code used in http request:
curl 'https://api.vapi.ai/call' \
-H 'authorization: Bearer YOUR_API_KEY' \
-H 'content-type: application/json' \
--data-raw '{
"assistantId": "YOUR_ASSISTANT_ID",
"transport": {
"provider": "vapi.websocket",
"audioFormat": {
"format": "pcm_s16le",
"container": "raw",
"sampleRate": 16000
}
}
}'
xml used in respond to webhook node:
Nikki
07/10/2025, 11:28 AMthis is the error that I encountered on twilio
https://cdn.discordapp.com/attachments/1392591484464660540/1392829914406846585/image.png?ex=6870f571&is=686fa3f1&hm=bb8865e1517ae8185fa25202bd984b3b96491b74e9b664735a4aee49440dae44&
Nikki
07/10/2025, 11:29 AMthe websocket gets connected but there is no audio transfer
c
Chiranjeet Mishra
07/12/2025, 6:34 AMHey Nikki,
Kings Big's actually out on an offsite right now, but he'll be able to dive into this for you on Monday, and help figure out the best approach for your setup.
Regards,
Shubham Bajaj
Solutions Engineer
Chiranjeet Mishra
07/26/2025, 1:41 PMHi,
First off, we want to sincerely apologize for the delay in getting back to you. We understand how frustrating it is to wait - especially when you're counting on us - and we owe you a clear explanation of what’s been happening and how we’re addressing it.
Over the past few weeks, we've seen a significant increase in support requests. While this reflects exciting growth, it has also stretched our small team and exposed some real challenges in scaling our support operations. To improve your experience, we’ve taken a step back to reassess our approach. Here’s what we’re implementing:
- Smarter Support Through Automation: We’re investing in our AI support systems to help you resolve issues more efficiently. Soon, our support bot will offer expanded capabilities, making it easier to access accurate, instant help—particularly for common or repetitive queries.
- Expanding the Support Team: To meet growing demand, we’re adding 2–3 new team members focused on managing support volume and improving response times.
- Prioritized SLAs for High-Usage Accounts: We’re introducing service level improvements for users who are growing with us:
- Accounts with usage over 1,000 minutes/month will receive prioritized support.
- For all general inquiries, we’re establishing a standardized 48-hour response time.
We’re confident these steps will lead to faster, more reliable support and help us better serve you as you grow with us. Also, in case you still need help with this ongoing ticket, do let us know, and we will help you get this resolved as soon as possible.
Thank you for your continued patience and for being part of our journey.
Warm regards,
Vapi Team
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