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

# Error Reference

In general, all responses come into the following types:

* **Informational responses** (100 – 199);
* **Successful responses** (200 – 299);
* **Redirection messages** (300 – 399);
* **Client error responses** (400 – 499);
* **Server error responses** (500 – 599).

If your request was successful, you will receive a response with code 200 or 201 and the queried data in JSON format. Otherwise, you get an error response explaining what went wrong with your request and how to retrieve the requested data.

Below are possible error responses you may get:

| **Response**           | **Code** | **Description**                                                                                                                                     |
| :--------------------- | :------- | :-------------------------------------------------------------------------------------------------------------------------------------------------- |
| Bad Request            | 400      | One or more query parameters are wrong <br />or missing.                                                                                            |
| Unauthorized           | 401      | Missing or invalid API key in the request <br />header.                                                                                             |
| Forbidden              | 403      | Endpoint unavailable. <br />This typically happens when you try to retrieve <br />data from a Pro endpoint without the required <br />subscription. |
| Not Found              | 404      | Requested address, transaction, coin, or <br />object not found – likely an invalid hash.                                                           |
| Method Not Allowed     | 405      | The request method is recognized, but <br />not supported by this resource.                                                                         |
| Request Timeout        | 408      | The server timeout was due to a slow request <br />caused by an idle connection.                                                                    |
| Payload Too Large      | 413      | Request exceeds server limits; connection may <br />close or include a Retry-After header.                                                          |
| Unsupported Media Type | 415      | The server rejected the request because the <br />data format is not supported.                                                                     |
| Too Many Requests      | 429      | Insufficient API credits or rate limit exceeded –<br />upgrade, wait, or reduce request frequency.                                                  |
| Internal Server Error  | 500      | The server has encountered a situation it <br />can't handle.                                                                                       |
| Gateway Timeout        | 504      | The server acting as a gateway cannot get <br />a response in time.                                                                                 |