Browse Definitions:

Internet problems

Here are:

  • Three rules-of-thumb for dealing with Internet problems
  • A table showing the most common codes and messages you're likely to see on your Web browser (HTTP), when accessing Usenet, using e-mail, or using the FTP protocol to upload or download files

Three Rules-of-Thumb for Dealing with Internet Problems

  1. If you get a message saying the domain name server (DNS) can't find your page and you're sure you've typed it in correctly or clicked on a valid link, try it again - TWO more times! (Sometimes packets don't get there!)
  2. If you get a "Not found" message, the page may be temporarily missing because of miscoding at the target site. Try it again tomorrow...or try the home page for the site and send e-mail asking them to restore the page.
  3. Be aware that sometimes a page you've visited recently may be coming from your cache (or the cache on a proxy server within your company). To get the "fresh" version of the page, click on "Reload" in your tool bar.

A Table Showing the Most Common Codes and Messages

Error message What it means What you can do
400 - Bad request You entered a URL that is not accepted as correct. Possibly the server being contacted doesn't recognize the document you are asking for or it may no longer exist. It is also possible that it is correct but you aren't authorized to access it. Check the URL to see if it's correctly spelled and that every letter is in the right (upper- or lower-) case. Check colons, numbers of slashes, and tildes.
401 - Unauthorized The site being accessed is protected and you either entered the incorrect password or the host does not want users coming from your domain to enter. Some sites will only allow specific domains to access the site. For example, some U.S. government sites (with the .gov top-level domain name) will only permit users coming from .gov or .edu (educational sites) to gain access. Or some educational sites only allow access from other educational sites. If you are sure you have access to the site, try typing the password again. If you don't have a password or your domain does not have access to the site, you won't be able to access it.
403 - Forbidden You are not permitted to access this document. It is either password-protected or the host does not want your domain to enter. See above.
404 - Not found The host server can't find the HTML document at the URL you've entered. Either you have mistyped the URL, the document no longer exists, or you've been given the wrong URL. If your URL ends in ".htm", try ".html" (and vice versa). To find out whether the site hosting the document is still active, delete everything after the last slash in the URL. If this doesn't work, try deleting the slash and adding .htm or .html to the end. If the site is still running, try and find the page from another location on the site that you can reach.
550 - xxxxxxxxx is not a known user Using e-mail, you sent a note to an e-mail address that isn't recognized at the mail server you've specified. The e-mail note got all the way to the mail server (so that part's right), but you may have entered the user part of the e-mail address incorrectly or the user may no longer have an account on that server. Make sure you entered the correct e-mail user name. If you suspect it's an old address or was mistyped in a note sent to you, try looking up a new address using the person's name. Try e-mail address finding tools.
Bad file request The form you're trying to access is not supported by your browser or there is an error in the form. Try using a different browser. If the problem persists or another browser is not available, send an e-mail note to the site's Webmaster.
Cannot add form submission result to bookmark list This error message occurs when you've submitted a search request and then try to save the result as a bookmark. Even though it may look like a valid address, the resulting page does not have a URL that can be reused so it can't be added to your bookmark list. Use the Save As command to save the page to your hard drive. Then you can open the saved HTML page in your browser and add that to your bookmark list.
Connection refused by host You're not permitted to access this document either because it's password-protected or the host doesn't permit your domain to enter. If you have access to the site and you know the password, try again, making sure you type it correctly and with the correct case.
Failed DNS lookup The URL you requested could not be translated into a valid Internet address by the domain name system. This is either a result of a mistake in the system or you could have mistakenly entered an incorrect URL. Mistakes in DNS lookups are a common occurrence. Simply clicking the Reload button may correct the error. If the error persists, you may have entered an incorrect host name. Try typing the URL again.
File contains no data The site you accessed doesn't contain any Web pages on it. It's possible that you're trying to access the site while the page is being uploaded. Try waiting a minute and clicking on the Reload button. Make sure that the URL is typed in correctly. If the problem persists, try again later.
Helper application not found You're trying to load a file of a type that your browser doesn't recognize. Most browsers can be enabled to view or load file types that they don't otherwise recognize. These files can be sound files, movie clips, graphics, ZIP archive files, or any other type of file you are trying to download. The dialog box that carries this message will tell you the file type that is missing. You can then follow your browser's instructions for assigning a viewer for each file format you wish to view online. It's often better to have certain file formats not assigned to helper applications for Internet browsers. When files are not assigned to helper applications, the dialog box you receive has a "Save to Disk" option. This can often be useful when you want to download files, such as ZIP archive files, to save them instead of extracting them right away.
Host unavailable The server computer that hosts this site could not be reached. The server may be offline or down for maintenance. Try clicking on the Reload button. If it still doesn't work, try again later.
Host unknown The server you're trying to reach is not connected, or you have lost your own connection. You may have also entered the URL incorrectly. Click the Reload button and try again. Occasionally, packets don't arrive on the Internet and a second try will work. Next, make sure you are connected to the Internet. If you have lost your connection, simply reconnect and try the URL again. If you still receive the error, check the URL for typos and case-sensitivity.
Network connection was refused by the server Some servers have limits on the number of people or request they can handle at a time. If you get this message, the server is probably too busy to handle one more user. When the server doesn't create its own message to handle this error, this generic message is displayed instead. Try clicking the Reload button until you connect. Or try again later.
NNTP server error This error occurs when you are trying to log on to a Usenet newsgroup. An NNTP server is part of your Internet service provider's software, so if this error occurs the software may be malfunctioning or the newsgroup does not exist. Make sure that the URL is typed correctly. If you still receive the error, wait a while and try again. If the problem still persists, contact your access provider and make them aware of the problem.
Permission denied This error occurs when you are connected with an FTP site and you are either uploading or downloading. Sometimes the site administrator doesn't want you to upload to the site, download a certain file, or access a certain directory. The site may also be too busy. Check that you are using the correct procedure to upload or download the file. Then keep trying until you succeed. If you still receive the error and know that you're able to upload or download to that site, contact the Webmaster by phone or e-mail.
Too many connections--try again later The limit to the number of people who can use the site at one time has been exceeded. You'll have to wait your turn. Keep clicking the Reload button until you connect or try again later when there is likely to be less traffic.
Too many users To avoid slow uploading and downloading rates, site administrators set a maximum number of users that can access the site at one time. Your request is one too many. Keep trying until you connect or try again later when there is less Internet traffic. Check to see whether the site has mirrors, and try one of those.
Unable to locate host The server is either down for maintenance or you may have lost your connection. Click the Reload button; sometimes there is an intermittent problem on the Internet. Then make sure you're connected to the Internet. If you have lost your connection, simply reconnect and try the URL again. If you still receive the error, check the URL for typos and case-sensitivity.
Unable to locate the server The server indicated in the URL you typed or clicked from either no longer exists or was entered incorrectly. Check the URL to see if everything is correct. Make sure that everything is correctly spelled and in the correct case (some servers are case-sensitive). You can also check with the source of the URL to verify that it is correct.
Viewer not found Your browser doesn't recognize files of this type. Most browsers can be extended to be able to view or load file types that are not otherwise recognized by browsers, such as movie or sound files. When this dialog box appears, search for a helper application that will open files of this format. Then follow your browser's instructions for assigning this viewer to open files of that format online.
You can't log on as an anonymous user This is another FTP error message. Most browsers submit "anonymous" as your user ID and your email address as your password. The FTP site you are connecting to may not allow "anonymous" access. This error will also occur when the FTP server is currently at its limit of "anonymous" users. Another possibility is that your browser doesn't support anonymous FTP access (for example, America Online's browser). Keep trying to access the FTP site until you succeed. Sometimes the FTP server is too busy. However, if you don't have a browser that allows anonymous FTP access or the site is password-protected, enter your user ID and password manually using FTP software such as WS_FTP or CuteFTP.
This was last updated in January 2007

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