Have you ever been surfing the net or working on your computer only to be confronted by an error message featuring a number that makes literally no sense to you at all? It’s very likely that you have, but what does it all mean?
Error codes are three digits long. If they start with a “1” (1XX) then they are for your information. If they start with a “2” (2XX) then they are indicating a successful connection attempt. An error number beginning with “3” (3XX) means “redirection” – that you must do something else before you can do what you set out to.
An error number beginning with “4” (4XX) means “Client Error”. This basically means there is a problem with your computer, rather than the server belonging to someone else.
Finally, an error number beginning with “5” (5XX) means that there is a server error, and that the website you are currently trying to access is being affected by an internal server issue.
There are indeed quite a few error messages out there, and knowing what they mean may make it easier for you to try and fix the issue. Failing that, by telling your IT administrator what the number was will make it easier for them to trace the problem.
Here are some of the most common error numbers:
Information
100 Continue
101 Switching protocols, or procedures
Success
200 Action completed successfully
201 Success! Request has been created following a POST command
202 Your request has been accepted for processing, but the processing isn’t finished
203 Computer only has partial information it needs to run
204 The server has received your request but there is no information to send back
205 Content has been reset
206 Your requested file was partially sent because the web page likely crashed or refreshed
Redirection
300 There are multiple choices available
301 File has been moved permanently. Directory requested instead of specific file. You will notice that index.html, index.htm, home.html, or home.htm has been added to the
302 Moved temporarily
304 The cached (hidden) version of the requested file is the same as the file to be sent, it’s not updated
305 A substitute file has been used (proxy)
Client error
400 Bad request! The server doesn’t understand. Clearing the cache should help.
401 Unauthorised access. You don’t have the correct access rights, user name or password
402 Payment is required for access
403 Forbidden! The file does not have permission that allows the pages to be viewed on the web
404 Not found. For whatever reason, the web page is not available. This could be that you’ve entered the wrong web address
Server error
500 Server error. Usually caused by a server that has not been configured properly
501 Not implemented
502 Bad gateway. This means that the server you're contacting is a gateway or proxy (substitute) server. It is not receiving a valid response from the main server that should actually be dealing with the request
503 Out of resources. This means that the system is overloaded
504 Gateway timed-out. A slow internet connection can be caused by multiple things, such as defective Ethernet cables, old switches, or general poor service. It could also mean the server is in need of maintenance
505 HTTP version is not supported
