Common HTTP Errors (Status Codes) and What They Mean

Ever get a 400,404, etc… error and wonder what it actually means? For most users of the internet we usually don’t care what they mean since a site is either up, or it’s down. For the other part of you that are interested in what the codes actually mean and what to do,  I thought I would list some of the common errors and what they are in basic terms so you know is going on next time you get one of these errors.

400 Level Status Codes (Client Errors)

Client errors are issues that occur on the end user’s computer, verses at the server or website you are connecting to. Most of the time it is still the website’s fault, but here are a errors to look for :

  • 400 (Bad Request) – This happens when the server couldn’t understand your web browser’s request. If you continue to get this message, try waiting a bit or switching web browsers.
  • 401 (Unauthorized) – You will get this error code when you attempt to log in to a website with a wrong username or password. Ensure both are correct, and try again.
  • 403 (Forbidden) – You will get this message if you are blocked for some reason from the server. Wait a few minutes, then try again. If you are getting the same message, I would attempt to email or contact the system administrator.
  • 404 (Not Found) – This is probably the most common error. This will display when a url is miss-typed or the content or media in which you are trying to access has been deleted. If you get this, make sure the link is typed correctly. If it was, then you are probably out luck since the item was deleted.
  • 405 (Method Not Allowed) – 99% of the time when you see this error, it won’t be your fault. This is an issue with the code on the server sending or receiving mismatched data, thus no output.
  • 408 (Request Time Out) – A 408 will appear when the speed of the connection is too low for the server. This can happen when you try to access a process heavy activity on a slow internet speed. If you get this, try going to google.com or another less load intensive website to see if your internet connection is down. If you have a connection, I would wait a few minutes to see if your speed increases and try again. NOTE : If you get this during a transaction with a merchant online, do not attempt to refresh. This will most likely charge you twice.
  • 410 (Gone) – Very similar to a 404 error except this means the server has knowledge this url once existed, but was moved. I would attempt to google for something similar or contact an admin to see where the page has gone.
  • 420 (Twitter Overload) – As the title states, you will get this if the twitter servers are over capacity. Most likely though they will display a more user friendly error message than just 420, but just in case, here it is.
  • 450 (Blocked by Windows Parental Controls) – You will get this if the parental controls controlling your browser refuses access to a page. Disable the Parental Controls to continue.

500 Level Status Codes (Server Errors)

Since server errors always occur on the server, there is nothing you can do. This portion of post is more for information.

  • 500 (Internal Server Error) – This will occur when there is an error in the programming or configuration on the web server or the software running on it.
  • 502 or 504 (Bad Gateway or Gateway Timeout) – You will get either of these errors when there is a communication error or slow connection between the back end computers, and not between yours (the client) and the server.
  • 503 (Service Unavailable) – This will occur when either there is an overload of the system or the site is currently undergoing some maintenance. Recently, companies will put up a maintenance message, so the system overloading will most likely be the issue.

Other Status Codes

The codes and statuses listed here are far from all the ones you will experience, but these are probably the only ones you will experience 99% of the time. If you would like a more complete listing, please visit one of the sites below.

For More Information :

Detailed technical information and complete listing :

http://en.wikipedia.org/wiki/List_of_HTTP_status_codes

Microsoft’s List of Errors :

http://windows.microsoft.com/en-US/windows-vista/Get-help-with-website-error-messages-HTTP-errors

Jacob Saylor

Software developer in Kentucky

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