# External SIP leg remains connected ~16–18 seconds after voicemail detection

**URL:** <https://community.retellai.com/t/external-sip-leg-remains-connected-16-18-seconds-after-voicemail-detection/3700>\
**Category:** Support Help\
**Tags:** telephony\
**Created:** [September 30, 2026, 6:30am UTC](https://community.retellai.com/t/external-sip-leg-remains-connected-16-18-seconds-after-voicemail-detection/3700 "2026-09-30T06:30:53Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![tornike\_777](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/tornike_777/32/2797_2.png) [@tornike\_777](https://community.retellai.com/u/tornike_777)\
**Post date:** [September 30, 2026, 6:30am UTC](https://community.retellai.com/t/external-sip-leg-remains-connected-16-18-seconds-after-voicemail-detection/3700/1 "2026-09-30T06:30:53Z")

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Hi,

We are using Retell for outbound calls with an external SIP trunk.

We have identified a consistent discrepancy on voicemail calls:

**Call ID:** `call_5b0c61b093316521499c5fa1a90`  
**Destination:** `+5492974738463`  
**Retell duration:** 2 seconds  
**Disconnection reason:** `voicemail_reached`

Retell Data Log:  
`2026-09-29 17:38:45.148 Starting call`  
`2026-09-29 17:39:04.876 Ending call`

Our telephony provider confirms that the SIP leg and phone leg were disconnected at **20:39:21** , with the hangup initiated by the SIP side.

So there appears to be approximately a **16–18 second delay between Retell ending the AI session and the SIP leg actually being disconnected**.

We have matched this pattern across many voicemail calls. Most of the duration discrepancy between Retell and the telephony provider comes from voicemail calls.

Our settings are:

- Voicemail Detection: enabled
- Hang up if reaching voicemail: enabled
- IVR Hangup: enabled

Retell’s documentation states that the call should disconnect immediately when voicemail is detected.

Could you please check the backend/SBC SIP trace for this Call ID and confirm:

1. The exact timestamp when Retell sent the SIP BYE
2. Whether there is any delay between `voicemail_reached` / internal call end and SIP BYE transmission
3. Whether there is any known issue or configuration affecting teardown timing with external SIP trunks

The extra connected time is billable by our telephony provider, so this is materially affecting our call economics.

Thanks.

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<div class="post-metadata">

**Author:** ![mark1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/mark1/32/2524_2.png) [@mark1](https://community.retellai.com/u/mark1)\
**Post date:** [September 30, 2026, 9:55am UTC](https://community.retellai.com/t/external-sip-leg-remains-connected-16-18-seconds-after-voicemail-detection/3700/2 "2026-09-30T09:55:39Z")

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Hey @tornike_777

Thanks for providing the detailed information and the Call ID. I’ve noted the SIP teardown timing discrepancy you’re seeing on voicemail calls.

We’ll review this further and get back to you as soon as we have more information.

Thank you!

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<div class="post-metadata">

**Author:** ![mark1](https://yyz2.discourse-cdn.com/flex008/user_avatar/community.retellai.com/mark1/32/2524_2.png) [@mark1](https://community.retellai.com/u/mark1)\
**Post date:** [October 1, 2026, 3:13pm UTC](https://community.retellai.com/t/external-sip-leg-remains-connected-16-18-seconds-after-voicemail-detection/3700/3 "2026-10-01T15:13:22Z")

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Hey @tornike_777

Just to confirm, the call ended after 2s on Retell, but the provider shows it lasted over 16s. Could you share the PCAP file from your side?

Best Regards.