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

# Errors

> HTTP status codes and error object schemas returned by Mailofly.

Mailofly uses conventional HTTP response codes to indicate request success or failure.

***

## Status Codes

| Code | Meaning |
| :- | :- |
| **`200 OK`** | Request succeeded. |
| **`201 Created`** | Resource created successfully. |
| **`400 Bad Request`** | Missing or malformed parameters. |
| **`401 Unauthorized`** | Missing or invalid API key. |
| **`403 Forbidden`** | Sender domain not verified or permission denied. |
| **`404 Not Found`** | Requested resource ID does not exist. |
| **`429 Too Many Requests`** | Rate limit exceeded. |
| **`500 Internal Error`** | Mailofly server issue. |

***

## Error Response Body

```json theme={null}
{
  "statusCode": 400,
  "message": "The 'to' field must contain at least one valid email address.",
  "name": "validation_error"
}
```


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