---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/80304#article
headline: "80304: Not Found Unmanaged Identifier"
url: https://www.twilio.com/docs/api/errors/80304
inLanguage: en
dateModified: 2026-06-08T12:04:59.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 80304: Not Found Unmanaged Identifier

Log Level: WARNING

## Description

Twilio returns this warning when Proxy cannot find the unmanaged `proxyIdentifier` you supplied for a Participant. In Proxy, a Participant `identifier` can be a phone number or a channel identifier. If you set `proxyIdentifier` yourself, it must be a valid proxy address for that Service. For phone-based flows, that means a Twilio phone number already available to the Service. For channel-based flows, that means a configured channel sender managed through your Proxy channel setup.

### Possible causes

* You supplied a non-phone `proxyIdentifier` for a channel that is not installed or configured for Proxy. Proxy channel integrations must be installed in Console before you use a channel sender as a proxy identifier.
* The channel `Callback Url` is not set to your Proxy Service webhook, so Proxy is not managing that channel sender for the Service.
* The `identifier` or `proxyIdentifier` does not use the expected channel address format. For channel-based Proxy sessions, the Participant `identifier` is the end user's channel ID and the `proxyIdentifier` is your channel sender ID.
* You specified a phone number as `proxyIdentifier`, but that Twilio phone number is not already added to the Proxy Service number pool. When you provide a phone-based `proxyIdentifier`, Proxy only accepts a Twilio phone number that is already associated with the Service.

### Possible solutions

* If you are creating a phone-based Participant, add the Twilio number to the Proxy Service number pool before you set it as `proxyIdentifier`. You can also omit `proxyIdentifier` and let Proxy select an appropriate number from the pool.
* If you are creating a channel-based Participant, install the channel in Console and set the channel `Callback Url` to your Proxy Service webhook.
* Use the correct values when you create the Participant. Set `identifier` to the end user's channel ID, such as `messenger:+1415XXXXXXX`. Set `proxyIdentifier` to your channel sender ID, such as `messenger:{page-id}`.
* Verify that you are using the correct `ServiceSid`. Proxy number pools and channel management are configured at the Service level.

#### Additional resources

* [Using Proxy with Channels](/docs/proxy/channels)
* [Participant resource](/docs/proxy/api/participant)
* [Service resource](/docs/proxy/api/service)