# 80623: Duplicate Participant Request

Log Type: APPLICATION

Log Level: ERROR

## Description

This error occurs when Proxy receives a request to create a Participant for an `Identifier` while another request for that same `Identifier` is still in progress in a different Session. Proxy rejects the request with a 409 conflict to prevent multiple active Participants from sharing the same `Identifier` and `ProxyIdentifier` pair, which can cause calls or messages to be routed incorrectly.

### Possible causes

* Your application sent multiple Participant create requests for the same `Identifier` at nearly the same time.
* A Session create request that included participant parameters ran while another Participant create request for the same `Identifier` was still being processed.
* Your application retried a Participant create request before the earlier request completed.
* The same participant is being added to multiple concurrent Sessions without coordinating request order.

### Possible solutions

* Create Participants for the same `Identifier` one request at a time instead of sending parallel requests.
* Include `FailOnParticipantConflict=true` in Participant create requests, or in Session create requests that include participant parameters, so Proxy can reject conflicting requests immediately.
* When you receive 80623, wait for the earlier conflicting request to complete and then retry the failed request.
* If the same participant must be active in multiple concurrent Sessions, add enough Twilio phone numbers to your Service so that participant can be assigned a unique Proxy number in each active Session.

#### Additional resources

* [Participant resource](/docs/proxy/api/participant)
* [Session resource](/docs/proxy/api/session)
* [How many Phone Numbers do I need?](/docs/proxy/phone-numbers-needed)