• An HTTP status code is a 3-digit code used to represent the status of an HTTP response from a web server.
  • The first digit of any status code represents one of the five states of the response.
  • When a user attempts to access content on a running host over HTTP or FTP, the Web server returns a numeric code indicating the status of the request.
  • This status code is recorded in the server log and may also be displayed in a Web browser or FTP client.
  • This is the code that displays the error message when we open the page in error. A status code can indicate whether a specific request has been successful and can also reveal the exact reason why the request failed.

The meaning of the HTTP protocol status code can be divided into five categories, which are generally as follows:

name val
1 x x: keep
2 x x: Indicates that the request was received successfully
3 x x: The customer needs to further refine the request to complete it
4 x x: Customer errors
5 x x: Server error

According to Google search data, the following are the most common errors, with HTTP 500 errors occurring twice as often as 404 errors:











Common status codes are:

  • 500 Internal server error

This is one of the most common HTTP errors amenable to the definition of HTTP 500 errors. In general, HTTP 500 – errors occur when the server’s code fails, or when the Web server experiences an internal error. – For example, the Web server cannot properly process access requests when overloaded.

  • 404 file not found

Most people are aware of this mistake. A 404 error occurs when a user tries to access a resource on a Web server (usually a Web page) that doesn’t actually exist. 404 error – This could be caused by an invalid link, a misspelled URL, or the virtual host moving the requested page somewhere else (or deleting the requested page). Some sites have custom pages to prevent the effects of bad links.

  • 403 Access Forbidden

The 403 error is similar to the 401 error, except that the 401 error is unauthorized and the 403 error prevents access. The 403 error does not apply to any login. – Error 403 occurs when you try to access the (prohibited) site directory.

  • 400 Error request

The Web server returns an HTTP 400 error telling the visitor that the program the visitor is using to access the site is faulty or that the access request has been corrupted.

  • 401 Unauthorized

The site returns an HTTP 401 error when a visitor tries to access a restricted page without authorization. An incorrect login attempt is the main cause of this error.

  • 200 Request succeeded

The request was successful, and the desired response header or data body is returned with this response.

  • Section 206

The server has successfully processed some of the GET requests. Http-download tools such as FlashGet or Xunlei use such responses to implement breakpoint continuation, or to split a large document into multiple download segments for simultaneous downloading.

  • 301 permanent redirect

The requested resource has been permanently moved to the new location, and any future references to this resource should use one of the several URIs returned by this response.

  • 302 Temporary redirect

The requested resource now temporarily responds to the request from a different URI. Since such redirects are temporary, the client should continue to send future requests to the original address.

  • 502 Invalid gateway

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