Common Errors While Browsing the Web

There are several common errors that can occur while web browsing, however, knowing what they mean may help resolve support issues. Are they a result of your computer or browser software? Or are they a result of web server errors? Review this mini-index of WWW error messages to assist in solving your online dilemmas.

400 - Bad request

A web page returning this message means the web server was unable to return the page(s) included in the URL (web address, i.e. http://www.address.com). It could be a problem with the web page you requested, possibly it has been moved and the link remains un-repaired. However, you should also check your spelling if you typed in the URL manually in the address or location field of your browser.
Frequently, you may find a slash or period out of place, or even the lower or upper case you used may be incorrect. If you are unable to access a page after repeated attempts, the only remedy is an e-mail to the web site's webmaster or the ISP servicing the web pages.

401 - Unauthorized

These are sites that provide password protected users admittance. Those without a valid password or possibly an authentication software (a digital certificate) will receive this error.

404 - Not Found or Object Not Found

This is frequently the result of a site author changing the location of an HTML document or downloadable file while not repairing a link. E-mail the site's administrator requesting the status of the link.

DNS lookup failure

This occurs when the Domain Name System (DNS) cannot lookup and verify the URL you typed in as a valid WWW address. This is a common Netscape error when an incorrect URL is typed in or the site you are seeking can no longer be found online. Double check your typing and also attempt to contact the site staff. If you are using the Internet via a Proxy Server, you may also fail if a site attempts Reverse Domain Lookup. This occurs due to the fact that you are using a single Internet address to represent many individuals. In addition, the Internet address is not in the DNS system for lookup (see http://www.networksolutions.com). A Proxy Server is a piece of software running on a computer that contains two connections - 1) to the Internet, 2) to a network (LAN) which authenticates users with passwords, and the allows them an anonymous connection to the Internet.

Plug-in or Helper not found and/or Viewer not found

This is the result of accessing a file from the Internet (possibly a PDF file, or compressed Zip file), and your browser cannot identify an appropriate piece of software on your computer to activate it. Check the file type at the source's web site, and then seek out a plug-in or downloadable application. Examples include Adobe Acrobat Reader (for PDF files), PKZip (compressed Zip files), Windows
Media Player, and many others. Check with the IT Department when this occurs.

Host unknown and Unable to locate host

Check to make sure you are logged in to your ISP (Internet Service Provider), your Local Area Network (LAN) or Proxy server, and that you typed the URL address correctly. The server hosting the web site may also be out of operation.