# Error codes (/en/realtime-media/rtm/reference/error-codes)

> For AI agents: see the complete documentation index at [llms.txt](/llms.txt).

This page lists the error codes returned by the Signaling SDK and RESTful APIs. Use these codes to help debug issues when developing applications with Agora Signaling.

## RESTful API error codes [#restful-api-error-codes]

When you call the Signaling RESTful API, each response includes the following fields:

* `errorCode`: The numeric status code returned by the server.
* `reason`: A description of the error associated with the code.

This section describes the meaning of each error code, provides possible causes, and offers suggested solutions.

| Error code | Reason                              | Details                                                                 | Suggested action                                                                                                                                            |
| ---------- | ----------------------------------- | ----------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `200`      | Success                             | The request was successful, and messages from history were returned.    | No action required.                                                                                                                                         |
| `400`      | Invalid request                     | The request contains invalid parameters.                                | Verify and correct the parameters.                                                                                                                          |
| `401`      | User authentication error           | The request contains invalid authentication parameters.                 | Verify and use valid parameters.                                                                                                                            |
| `403`      | Unauthorized or feature not enabled | The App ID is invalid or does not have access to the required features. | - Verify that the App ID is correct.<br/>- Confirm that the Signaling service is enabled.<br/>- Confirm that the history feature is enabled for the App ID. |
| `408`      | No response from the server         | The request timed out.                                                  | Try again later.                                                                                                                                            |
| `415`      | Unsupported media type              | The request body format is not supported. Only JSON is accepted.        | Ensure the request body is formatted as JSON.                                                                                                               |
| `429`      | Rate limit exceeded                 | The number of requests exceeds the allowed limit.                       | The quota for the RESTful API is 60 requests per second. Reduce the request rate.                                                                           |
| `435`      | Invalid payload                     | The message payload contains illegal or unsupported content.            | Modify the payload and resend the request.                                                                                                                  |
| `500`      | Internal server error               | An unexpected error occurred on the server.                             | Retry the request.                                                                                                                                          |
| `503`      | Timeout                             | The request took too long to process.                                   | Retry the request.                                                                                                                                          |

## SDK error codes [#sdk-error-codes]

When calling Signaling SDK APIs, failures are typically returned through the SDK callback result or error object for the current platform. The payload usually includes:

* `errorCode`: The SDK error code for the current operation.
* `reason`: A description of the error.
* `operation`: The operation that triggered the error, when available.

For currently maintained SDK-side error handling details, see:

* [Troubleshooting](./troubleshooting) for logging setup and the SDK error payload structure available in this portal.
* [Signaling API reference](/en/api-reference/api-ref/signaling) for platform-specific SDK enumerations, callback contracts, and error-related data structures.