Web Browser Error Messages

There are several common error messages you can receive when visiting a web site.

The most frequent web error message is 404 Not Found, returned by the destination web server when the URL is misspelled or the page no longer exists. The most common web error messages and their causes are summarized in the table below. Additional error codes are described in sections 10.4 and 10.5 of RFC 2616.



400 Bad Request

The site was found, but the page could not be found. Check the spelling of the URL carefully, including the upper and lower case of the letters. If you still can’t find the page, see Finding A Missing Link, and The Virtual City Model.

401 Unauthorized

Page exists but is only accessible to specified users (not you). Possibly the site or page has been temporarily taken off-line for maintenance or other activity.

403 Forbidden Page

Same as “401 Unauthorized” above.

404 File Not Found

Same as “400 Bad Request” above. See the summary at the beginning of this section.

500 Page Unavailable

This page is unavailable at the moment. Please try again shortly.

503 Service Unavailable

The site is busy, or service has been temporarily suspended. Try again later.

Bad file

Either your browser doesn’t support a feature in the accessed page, or there is an HTML error in the page. Try upgrading your browser to the latest release, or seeing if anyone else can access the page.

Connection refused

Either the site is serving the maximum number of users, or is temporarily closed to public access. Try again later.

Connection reset by peer

For some reason the remote side terminated the connection. Try again. If this repeats on one site, there is something wrong with the site. If it repeats on more than one site, you probably have a bad line connection.

Document contains no data

The page was found, but is empty. It may be being updated. Try again later.

Fatal Error. System call ‘fopen’ failed: No such file or directory.

Page has moved, or the URL is wrong.

Failed DNS lookup

The site cannot be found. Check your spelling. If your spelling is correct, the site has been removed (temporarily or permanently) from the Internet.

File Contains No Data

Same as “Document Contains No Data” above.

Forbidden – Your client is not allowed to access the requested object

Same as “401 Unauthorized” above.

Helper application not found

You tried to access a file for which your browser needs a special helper application. Check the file type referenced in the message, and add the appropriate helper application.

Host unavailable

The site exists, but is not presently accessible. If you can’t access any other site either, then your ISP is down. Otherwise, the site has been taken off the Internet, possibly only temporarily for maintenance. Try again later.

Network connection was refused by the server

The site is probably just too busy, or down for maintenance. Try again later.

Server does not have a DNS entry

Same as “Failed DNS lookup” above.

Too Many Connections – Try Again Later

The site is serving the maximum number of users. Every few minutes try pressing Reload or Refresh until you gain access.

Unable to locate host

Same as “Host unavailable” above.

You can’t log on as an anonymous user

Usually caused when trying to access an FTP site. The site may already have the maximum number of anonymous users logged in, in which case you should try later. If you still can’t get in, it may be that the site does not allow anonymous logins, in which case you will have to use an FTP program to log in with a valid user name.