Call Transfer to Extension not working when 'Displayed Caller ID' is set to "User's Number" with Retell Twilio number

Support Help
1

Hey, am using a twilio phone number that i bought from Retell. During Call Transfer, if I select ‘Displayed Caller ID’ as “User’s Number”, the call is getting transferred to main number, but the the extension is not working. But when I select ‘Displayed Caller ID’ as “Retell Agent’s Number”, the call is getting transferred to main number and extension number as well.

In the docs it says that if we use a Retell Twilio number it should work but it still doesnt - how can i fix this?

I also tried Telnyx number that we bought ourselves (not using Retell) and it still doesnt work.

2

Hello @liana1 Hey, could you please share your Agent ID and the relevant Call ID? This will help us investigate the issue further.

Thank You

3

Yes, call_0d18c09701850f16e68fc98f574 and agent_58e3fc9f611030ba14794c7ab7
Extension did not work

4

Hey @liana1 I’m checking this with the team and will get back to you as soon as I have an update.

5

Hello @liana1 The transfer was a warm transfer with Human Detection ON, dialing an IVR (Better Night’s menu). Extension DTMF is only played after human detection succeeds — the IVR never speaks like a human, detection timed out (“Call connected but no human response detected”), and 7620# was never dialed.
Fix for this call: set optOutHumanDetection: true on the transfer_call tool (or switch to cold transfer). Then the extension will DTMF into the IVR.

Thank You