---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/45310#article
headline: "45310: Participant Not Found"
url: https://www.twilio.com/docs/api/errors/45310
inLanguage: en
dateModified: 2026-06-09T11:00:42.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 45310: Participant Not Found

Log Type: APPLICATION

Log Level: ERROR

## Description

This error means Flex couldn't find the participant you tried to manage in a live meeting or conference-based call. Flex can only act on active participants in an in-progress conference. If the participant's call ended, the conference ended, or the call was modified to use new TwiML, the participant is no longer available for participant actions.

### Possible causes

* The participant disconnected or was removed from the live call before Flex completed the action.
* The conference ended and no longer has any active participants to manage.
* The call was modified to use new TwiML, so the original participant is no longer part of the active conference state.
* The action was attempted after the call stopped meeting the live conference-based requirements used by features such as warm transfer or call monitoring.

### Possible solutions

* Confirm that the interaction is still live and conference-based, then retry the action against the current participant state.
* If you are using warm transfer, make sure the call is live, you are not on hold, and another transfer is not already in progress.
* If the participant already left the call, start a new consult or monitoring session, or add the participant back to the active call if needed.
* Review the Flex Status Report or Twilio Debugger for more detail about the failure. If the issue continues, run System checkup in Console to identify Flex configuration issues.

#### Additional resources

* [Warm transfer](/docs/flex/end-user-guide/warm-transfer)
* [Monitor agent activity](/docs/flex/end-user-guide/real-time-reporting/monitor-agent-activity)
* [Conferences Participants subresource](/docs/voice/api/conference-participant-resource)