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

# Errors

Possible API errors are as follows:

| Code                                                       | Text                  | Description                                                                                                                                                                                                        |
| ---------------------------------------------------------- | --------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| [400](https://en.wikipedia.org/wiki/Http_status_codes#400) | Bad Request           | Missing or invalid parameter. Possible causes: - malformed request parameters.                                                                                                                                     |
| [401](https://en.wikipedia.org/wiki/Http_status_codes#401) | Unauthorized          | Authorization is missing or incorrect. Possible causes: - a user tries to authorize with a wrong login or password. - a user uses invalid session token.                                                           |
| [403](https://en.wikipedia.org/wiki/Http_status_codes#403) | Forbidden             | Access has been refused. Possible causes: - a user tries to retrieve chat messages for a chat dialog while they are not in the occupants list.                                                                     |
| [404](https://en.wikipedia.org/wiki/Http_status_codes#404) | Not Found             | The requested resource could not be found. Possible causes: - a user tries to retrieve chat messages for the invalid chat dialog ID. - a user tries to retrieve a custom object record with invalid ID.            |
| [422](https://en.wikipedia.org/wiki/Http_status_codes#422) | Unprocessable Entity  | The request was well-formed but was unable to be followed due to validation errors. Possible causes: - create a user with the existent login or email. - provide values in the wrong format to create some object. |
| [429](https://en.wikipedia.org/wiki/Http_status_codes#429) | Too Many Requests     | Rate limit for your [current plan](https://quickblox.com/pricing/) is exceeded.                                                                                                                                    |
| [500](https://en.wikipedia.org/wiki/Http_status_codes#500) | Internal Server Error | Server encountered an error, try again later.                                                                                                                                                                      |
| [503](https://en.wikipedia.org/wiki/Http_status_codes#503) | Service Unavailable   | Server is at capacity, try again later.                                                                                                                                                                            |