# Definition of HTTP Status Error Codes

HTTP status error codes indicate the outcome of a request and help identify issues in client-server communication. This document provides an overview of common error codes, including their descriptions and possible causes, to help troubleshoot and resolve problems effectively.

* **400 Bad Request:**
  * Description: The server cannot understand or process the request due to a client error.
  * Reasons: The request may contain incorrect parameters, be improperly formatted, or include incompatible request content.
* **401 Unauthorized:**
  * Description: The request lacks valid authentication credentials for the target resource.
  * Reasons: The user does not have the necessary permissions to access a protected resource, or the authentication credentials are invalid.
* **403 Forbidden:**
  * Description: The server understood the request, but the server refuses to authorize it.
  * Reasons: The user lacks the necessary permissions to access the requested resource.
* **404 Not Found:**
  * Description: The server cannot find the requested resource.
  * Reasons: The specified URL or file does not exist on the server.
* **429 Too Many Requests:**
  * Description: The user has sent too many requests in a given amount of time.
  * Reasons: The server has applied a rate-limiting mechanism due to frequently repeated requests.
* **500 Internal Server Error:**
  * Description: The server encountered an internal error and cannot fulfill the request.
  * Reasons: An unexpected condition occurred on the server, preventing it from processing the request.