Twilio Inbound Call Disconnects After DTMF Input When Integrated with ServiceNow Voice

[dev101]

Hi everyone,

I'm currently testing a ServiceNow Voice integration with Twilio and have encountered an issue with inbound calls.

Scenario

1. A caller places a call from a private/mobile phone to a Twilio phone number.
2. The call is successfully received by Twilio.
3. When the caller enters a keypad selection (DTMF input), the call immediately disconnects.
4. Reviewing the Twilio logs shows the call status as Completed rather than Failed.
5. Because Twilio reports the call as completed, I'm suspecting the disconnect may be occurring on the ServiceNow side of the integration.

Troubleshooting Performed

• Verified the inbound phone number configuration in Twilio.
• Reviewed Twilio Voice logs and call events.
• Confirmed the call reaches Twilio successfully.
• Observed that the disconnect occurs immediately after entering a keypad selection.
• No obvious error is displayed in Twilio, as the call is marked as completed.

Questions

• Has anyone experienced inbound calls disconnecting immediately after DTMF input when using ServiceNow Voice with Twilio?
• Are there specific ServiceNow Voice, Virtual Agent, or Telephony configurations that could cause the call to terminate after a digit is entered?
• Are there any ServiceNow logs or diagnostic locations that would help identify why the call is ending?

Any guidance or troubleshooting suggestions would be greatly appreciated.

Thanks!

[Vikram Reddy]

Hi @dev101,

This is usually the WebSocket side of Twilio's ConversationRelay stream closing right after the DTMF event, not Twilio actually failing the call, which is why it still logs as Completed instead of Failed. ServiceNow Voice connects to Twilio through a Connect/ConversationRelay stream, and keypad digits only arrive as a separate dtmf message when dtmfDetection is turned on for that stream; if the AI Voice Service backend errors while handling that message, say a signature check failing or an unhandled event type, it just closes the socket, and Twilio reads a clean socket close as a normal end of call rather than a failure.

Pull the Twilio Voice Insights trace for the exact timestamp the WebSocket closed, then check the ServiceNow transaction log around that same moment for a Request signature validation failed error against the AI Voice Agent REST endpoint, that combination is what nailed down a very similar case. Share those two timestamps if you're still stuck and I can dig further.

References

• TwiML Voice: ConversationRelay (dtmfDetection attribute)
• Troubleshooting my first AI Voice Agent - ServiceNow Community
• Integrate voice service with Twilio - ServiceNow Docs

Thank you,
Vikram Karety
Octigo Solutions INC

[Tanushree Maiti]

Hi @dev101 

Ref: Troubleshooting Dropped Twilio Voice Calls 

Virtual Agent conversation ends with a technical issues error - Support and Troubleshooting KB096737...