> ## Documentation Index
> Fetch the complete documentation index at: https://www.cometchat.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Error Codes

> Error Codes for CometChat REST API.

Error codes specific to the Notification APIs.

## Authentication Errors

| Error Code                  | Description                                                     |
| --------------------------- | --------------------------------------------------------------- |
| `AUTH_ERR_EMPTY_APIKEY`     | The `apikey` header is missing from the request.                |
| `AUTH_ERR_APIKEY_NOT_FOUND` | The provided API key is invalid.                                |
| `AUTH_ERR_NO_ACCESS`        | The API key doesn't have the required scope for this operation. |

## Provider Errors

| Error Code                    | Description                                            |
| ----------------------------- | ------------------------------------------------------ |
| `ERR_PROVIDER_NOT_FOUND`      | The specified provider does not exist.                 |
| `ERR_PROVIDER_ALREADY_EXISTS` | A provider with the same configuration already exists. |

## Push Token Errors

| Error Code                 | Description                              |
| -------------------------- | ---------------------------------------- |
| `ERR_TOKEN_NOT_FOUND`      | The specified push token does not exist. |
| `ERR_TOKEN_ALREADY_EXISTS` | The push token is already registered.    |

## General Errors

| Error Code             | Description                                 |
| ---------------------- | ------------------------------------------- |
| `ERR_BAD_REQUEST`      | Validation error in the request body.       |
| `ERR_OPERATION_FAILED` | The operation failed due to a server error. |