Knowledgebase

HTTP codes describe the status of a URL when a visitor tries to access it, and include error messages that result when visitors encounter problems on a website. The codes are three-digit numbers.

There are five classes of HTTP codes, which are divided into categories by the first digit.

• A first digit of 1, 2, or 3 represents a fully functional request.
• A first digit of 4 represents a client-side error. The most common codes span 400 to 404.
• A first digit of 5 represents a server-side error. Common codes span 500 to 510.

4xx Errors

Although these errors are technically the result of a problem with the client's (for example, the browser's) request, they often point to a problem on a website. For example, if a faulty link is on your home page, and visitors click it, they may see a 404 error.

For this reason, it is important to monitor these errors and investigate their causes. Because these are also among the highest-profile codes (visitors see them the most), you may want to customize the error page for them in cPanel.

400 Bad Request

The user's request contains incorrect syntax.

401 Unauthorized

The requested file requires authentication (a username 
and password).

403 Forbidden

The server will not allow the visitor to access the requested file. If a visitor sees this code in error, check the file's permission settings. You can also check to see whether the file has been protected through cPanel's index manager.

404 Not Found

The server could not find the file that the visitor requested. This error commonly occurs when a URL is mistyped.

5xx Errors

These errors are caused when a server is unable to fulfill an apparently valid request from a visitor. Often, you will need the help of a server administrator in order to investigate these errors.

It is also important to consider that many times, a chain of servers handles an HTTP request, so that it may not be the actual web server that returned the error.

500 Internal Server Error

This error signifies that the server has encountered an unexpected condition. It is a “catch-all” error that will be displayed when no specific information can be gathered by the server about the condition. This error often occurs when an application request cannot be fulfilled because the application was misconfigured.

501 Not Implemented

This signifies that the HTTP method that was sent by the client is not supported by the server. This happens most often if the server is out of date. This error is very rare and generally requires that the web server be updated.

502 Bad Gateway

This error is usually due to improperly configured proxy servers. However, the problem may also arise when there is poor IP communication between backend computers, when the client’s ISP is overloaded, or when a firewall functions improperly.

The first step to resolve the issue is to clear the client’s cache. This action should result in the use of a different proxy to resolve the web server’s content.

503 Service Unavailable

This error occurs when the server is unable to handle requests because of a temporary overload or if the server is temporarily closed for maintenance. The error signifies that the server will only temporarily be down. It is possible to receive other errors in place of 503.

504 Gateway Timeout

This occurs when a server somewhere along the chain does not receive a timely response from a server further up the chain. The problem is caused entirely by slow communication between upstream computers.

505 HTTP Version Not Supported

This error occurs when the server refuses to support the HTTP protocol that has been specified by the client computer. It can be caused if the protocol is not specified properly by the client computer (for example, if an invalid version number has been specified).

This error will not be an issue with a current installation of cPanel.

506 Variant Also Negotiates

This error indicates that the server is not properly configured.

507 Insufficient Storage

This code indicates that the server is out of free memory. It is most likely to occur when an application that is requested cannot allocate the necessary system resources for it to run.

509 Bandwidth Limit Exceeded

This error occurs when your account's bandwidth limit has been reached. Please consider upgrading your hosting account to the next higher package to accommodate your bandwidth requirements. Or you can wait until the limit is reset in the following cycle which is the 1st day of the following month.

510 Not Extended

This error occurs when an extension that is attached to the HTTP request is not supported by the web server.