Here are some of the more common error codes and descriptions of the errors, that you might find when you click on a Hyperlink.

The 400 series of Web error codes indicate an error with your Web browser
The 500 series of Web error codes indicate an error with the Web server

Bad request 400:

This is a fairly common error and basically means that the requested document could not be sent because of syntax error in the URL (site address)

Unauthorized 401:

This is one of the most common error messages and usually means that the Server is expecting some sort of encryption id from the browser

Forbidden 403:

The document you are requesting is "forbidden" meaning that you do not have read privileges or are not allowed to have the page sent to you

Not found 404:

This is the most common and is similar to the 400 error. Basically this means that the document you have requested no longer exists or that the URL (site address) is incorrect

Internal Error 500:

The server was unable to send the html document to you due to an internal (server software) error

Not implemented 501:

This error occurs when for example, you have pressed the submit button on a form. The server reply's with this error message because it doesn't support the feature that you have requested. This is not a real common error, but typically occurs when new features or forms are implemented

Service temporarily overloaded 502:

The server cannot process the request due to a high load - The solution is to try later at a time when net load or server traffic is lower

Gateway Time-out 503:

The connection between the Web server and the browser has timed out due to server problems Internet problems or browser problems

Failed DNS Lookup

The IP address of the Web site could not be located by the ISP's domain name server or the server is too burdened to process the request