---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/45211#article
headline: "45211: Provided identity is reserved by system"
url: https://www.twilio.com/docs/api/errors/45211
inLanguage: en
dateModified: 2026-06-08T11:29:20.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 45211: Provided identity is reserved by system

Log Type: APPLICATION

Log Level: ERROR

## Description

This error occurs when you create a Flex Chat Channel and the required `identity` value is one that the system reserves for internal use. The `identity` parameter uniquely identifies the chat user for the new channel, so you must send your own valid user identity in the request.

### Possible causes

* You sent a reserved value in the `identity` field while creating a channel with `POST /Channels`.
* Your channel creation logic is assigning a system-reserved identity instead of a unique identity for the chat user. Flex requires `identity` for channel creation, and custom chat integrations also rely on a unique user identity.
* Your application is reusing an identity value that is not intended for customer identities in Flex messaging. Flex Flows connect messaging identities to Flex, and the channel request must provide a valid chat user identity.

### Possible solutions

* Change the `identity` value in your request to a different valid identity and try again.
* Make sure the `identity` you send uniquely identifies the chat user for the channel you are creating.
* If you use a custom chat integration, generate identities from your own customer or application user IDs instead of hardcoded system-style values.
* Do not use PII such as a phone number or email address as a custom chat identity. Use a stable application identifier instead.
* Review the code that creates the Flex channel and confirm it sends the correct `flexFlowSid` and a valid non-reserved `identity` for the user.

#### Additional resources

* [Flex Chat Channel Resource](/docs/flex/developer/messaging/chat-channel)
* [Manage Flex Flows](/docs/flex/developer/messaging/manage-flows)
* [Integrate a Custom Chat Client with Flex](/docs/flex/developer/messaging/integrate-custom-chat-client)