HTTP Error codes and it’s meanings

HTTP Error codes and it’s meanings

Please find below HTTP Error codes and it’s meaning –

When accessing a web server or application, every HTTP request that is received by a server is responded to with an HTTP status code. HTTP status codes are three-digit codes,and are grouped into five different classes. The class of a status code can be quickly identified by its first digit:

  • 1xx: Informational
  • 2xx: Success
  • 3xx: Redirection
  • 4xx: Client Error
  • 5xx: Server Error

The most commonly encountered HTTP error codes, i.e. 4xx and 5xx status codes, from a system administrator’s perspective.

400 Bad Request:

The 400 status code, or Bad Request error, means the HTTP request that was sent to the server has invalid syntax. Sometimes the user’s cookie that is associated with the site is corrupt. Clearing the browser’s cache and cookies could solve this issue.

401 Unauthorized:

The 401 status code, or an Unauthorized error, means that the user trying to access the resource has not been authenticated or has not been authenticated correctly. This means that the user must provide credentials to be able to view the protected resource.

403 Forbidden:

The 403 status code, or a Forbidden error, means that the user made a valid request but the server is refusing to serve the request, due to a lack of permission to access the requested resource. 403 errors commonly occur when the user that is running the web server process does not have sufficient permissions to read the file that is being accessed.

404 Not Found:

The 404 status code, or a Not Found error, means that the user is able to communicate with the server but it is unable to locate the requested file or resource. 404 errors can occur in a large variety of situations.

500 Internal Server Error:

The 500 status code, or Internal Server Error, means that server cannot process the request for an unknown reason. Sometimes this code will appear when more specific 5xx errors are more appropriate.

This most common cause for this error is server misconfiguration (e.g. a malformed .htaccess file) or missing packages

502 Bad Gateway:

The 502 status code, or Bad Gateway error, means that the server is a gateway or proxy server, and it is not receiving a valid response from the backend servers that should actually fulfill the request.

503 Service Unavailable:

The 503 status code, or Service Unavailable error, means that the server is overloaded or under maintenance. This error implies that the service should become available at some point. If the server is not under maintenance, this can indicate that the server does not have enough CPU or memory resources to handle all of the incoming requests, or that the web server needs to be configured to allow more users, threads, or processes.

504 Gateway Timeout:

The 504 status code, or Gateway Timeout error, means that the server is a gateway or proxy server, and it is not receiving a response from the backend servers within the allowed time period. This typically occurs in the following situations:

  • The network connection between the servers is poor
  • The backend server that is fulfilling the request is too slow, due to poor performance

The gateway or proxy server’s timeout duration is too short.


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