HTTP Error Messages

The HTTP protocol is used by web browsers and web servers to exchange information and requests for information. As part of the protocol servers return status information in the form of three digit numbers.

Below is a list of common and not-so-common error messages, what they mean and what to do about them if they appear on your website. Also listed are status messages which are used internally but will rarely if ever be visible to a user.

If these error messages occur on your website it reflects badly on your business, so you need to know about it. Website Repairs' free utility, Website Uptime will keep an eye on your website, and alert you if there are problems. Download it here.

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Quick Links

100 | 200 | 300 | 400 | 500

100 - 101 : Information

Items in this range aren't strictly errors and ought not be seen by most users. They are included for completeness.

100 - Continue: Part of the HTTP protocol allows a client to send an initial query to check that a server will accept a certain type of request. The server responds 100 - Continue, to indicate the request will be accepted and it is OK to send the actual request.
101 - Switching Protocols: The client has asked to switch from one protocol to another, e.g. from HTTP to FTP, and the server is indicating that it is complying with the request.

200 - 206 : Success

Items in this range aren't strictly errors and ought not be seen by most users. They are included for completeness.

200 - OK: The server is informing the browser that the document which has been requested is available.
201 - Created: On certain types of content managed sites, this response is sent to the browser when new content is created.
202 - Accepted: The server sends this message to indicate it has accepted the request.
203 - Non-Authoritative Information: The server is returning some content, but that content did not (all) come from this server - some of it may have come from another server or a copy.
204 - No Content: The server was able to service the request, but the document was empty. In this case most browsers will stay on the same page and will not switch to a blank screen.
205 - Reset Content: Once the server has sent content to the browser, and the source of the request should be reset. For example, if the previous request was e.g. via a form submission, then the browser should reset the form.
206 - Partial Content: The server has sent part of the total content to the browser. The browser should request that the remainder be sent.

300 - 307 : Redirect

Most of these messages are used by web servers to inform the browser of a change in address of a document, and are rarely seen by a user. Problems do occasionally occur, however, resulting in the error message being displayed on the browser.

300 - Multiple Choices: This occurs when the server can't decide what document to send based on the URL. It often means a file is missing or a link is mistyped or incomplete.
301 - Moved Permanently: This indicates that a link points to a document which has moved somewhere else. This can happen when a site is restructured. The server has updated the request URL and will return the correct document, but you should check your sites links to make sure they are all pointing to the new location(s).
302 - Moved Temporarily: This indicates that a link points to a document which has moved somewhere else but is likely to move back to it's original location.
303 - See Other: The request points to a document which is not the correct one, and the server should provide the correct address. At this point the browser will resubmit the request to the correct URL. This is only really a problem if, for example, the new URL is an incorrect one or points back to the original - then you need to examine the server configuration to correct the error.
304 - Not Modified: This code is used by the server to tell the browser that the document is available but has not been modified since it was last retrieved.
305 - Use Proxy: This message indicates that the browser must access the document via a particular proxy server.

400 - 417 : Client Error

Despite the general name for this group (Client Error) errors in this range can indicate a problem with your website or your server.

400 - Bad Request: The web server was unable to work out what the URL you sent to it meant. If you get this error when following a link from your website then it is likely that there is a typo in the link.
It can also appear if there is a problem with the server's configuration, for example on Apache servers, a .htaccess file with a Rewrite rule will generate this error if the server is not configured to support rewrite, so check your server configuration.
401 - Unauthorised: You have tried to access a page which is protected and you don't have permission to access it. This error might appear if a page if you mistype your user name or password. If you are sure you have typed your userid and password correctly, check that you aren't using the wrong case. The words "Password" and "PASSWORD" are different as far as the web server is concerned.
This error message might also appear if a page has become protected which shouldn't be.
402 - Payment Required: Have you paid your hosting bill? This error appears if there is a problem with your account. Contact your hosting provider for assistance.
403 - Forbidden: There are a number of reasons for this error.
If your site is configured not to allow directory browsing, and you have linked to a directory rather than a file within it, but you expected the link to be OK, then it is most likely that there is no index page in that directory.
If you recently moved your page from one host to another, some ISPs return this error if your websites new home hasn't been established yet by the internet Name servers. Wait 24 hours and try again.
Your server might be configured to reject connection requests from all but known browsers. This might have been done, for example, because you only want human visitors, and don't want to serve pages to over-zealous automated programs. If you are using a browser which isn't included in the "allow" list, then the server might respond with this error.
Your server might be reporting 403 instead of 401 or 404, so if you can't resolve it with the information for 403 try the suggestions for those errors.
404 - Not Found: This is perhaps the most common error you will encounter, and occurs when a page has been removed, or a link to a page is misspelled. Like error 403, it can also occur when a page has been moved to another server and the internet Name Servers have not yet been updated.
405 - Method Not Allowed: You are using a method to access the page which is not allowed. For example you are trying to use a POST request and the server does not allow it. If you clicked a button or followed a link from your site then check that the destination page for that button can accept the type of connection which is requested.
406 - Not Acceptable: The server is unable to service the request. This might happen because the request is for a content type that the server does not know how to send or because the request was for one type of content but the server must send content of a different type. NOrmally this message is not seen by users, although it might result in the web browser asking the user whether they wish to proceed.
407 - Proxy Authentication Required: This is similar to 401 - Unauthorized but instead of authorising with the server directly, the user must authorize with a proxy before attempting to retrieve the document.
408 - Request Timeout: The browser did not provide a request within the time the server is prepared to wait. This might indicate a misconfigured server but is more likely to result from a client having a slow connection to the internet.
409 - Conflict: This usually occurs in response to a PUT request trying to update a resource on the server which is subject to versioning, and the update would conflict with an earlier update.
410 - Gone: The requested document is no longer on this server and will not be replaced. This code should only be used for a relatively short time after a resource is removed and once that time has elapsed the error should revert to 404. It is up to the discretion of individual website owners how long that time should be.
411 - Length Required: The server requires that the browser send a content-length header to indicate how much data it will send.
412 - Precondition Failed: This is used when a client requires certain preconditions before it retrieves data, and those preconditions have not been fulfilled.
413 - Request Entity Too Large: The request would result in the server trying to send something to the client that is bigger than the server is able or willing to send.
414 - Request URI Too Long: The server is refusing to service a request because the request address is too long. If you get this error when you click on a linkon your site, you need to check the link. It might be caused by an unclosed <a> tag, or an automatically generated link being written incorrectly, perhaps due to a runaway loop in a script.
415 - Unsupported Media Type: The web server is refusing to send back the document as it is in an unsupported format. This error is rarely, if ever, seen by a web browser, and when it does occur it most likely indicates an error in the server configuration.

500 - 505 : Server Error

500 - Internal Server Error: This rather unhelpful message just tells you that "something went wrong" with the server. It can have a variety of causes, but often indicates an problem in the server's configuration.
501 - Not Implemented: This is more likely to indicate a problem with the browser than the server, and suggests that the browser has sent a non-standard request method.
502 - Bad Gateway: This response is normally received from proxy servers and indicates that the server it is attempting to connect to returned an invalid response. It might indicate a problem with your web server, or it might simply be that another proxy server between the browser and your website is behaving incorrectly. Try connecting without a proxy to check the status of your website.
503 - Service Unavailable: The server is temporarily overloaded. This might mean that you have too many users connected at the same time, or it might mean that another site hosted on the same server is taking too much of the available capacity.
504 - Gateway Timeout: This response from a proxy server indicates that the server it tried to connect to did not respond within a predetermined time. This could indicate that your website is unavailable. Try connecting without a proxy to check the status of your website.
505 - HTTP Version Not Supported: This error means that the server is unable to support the HTTP version used by the browser. This error should not occur with modern servers unless the client is using a very old browser.

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