## Introduction

Errors while attempting to retrieve a document or page from a WWW server can be caused by many things. There are 3 broad categories of error:

1. Network failure.

The client program is unable to locate or connect to the server. This is frequently caused by a bad URL (Uniform Resource Locator). Usually the client program gives an error message like: `Unable to connect to server`.

2. Server failure, no response.

If the client can establish a connection to the server but gets no sensible response, you usually get an error message to that effect. This type of error is usually the hardest to diagnose and correct, unfortunately.

3. Server detected error, sends diagnositic.

In this case the server sends a valid HTTP response to the request whose contents is a diagnostic error message rather than the intended information. When the server at Region 6 does this, the response contains a 1-line error description, prefaced with -ERROR-, and a dump of the failed request and header lines it received from the client. A link to a non-existent document, for example, will produce such an error.

## Common error messages

Below are the common error messages generated by server with a description of their cause and possible corrective measures or workarounds.

`no such file or directory`
  The server successfully parsed the request but did not find the file specified in the request. The document in question may have been deleted or moved, or the URL specified was mistyped.
`not owner`
  The server successfully parsed the request but does not have privilege to read the file specified in the request. The document in question is either not intended for public access or inadvertantly set to the wrong protection.
`Access to object is _ruled_ out.`
  The server successfully parsed the request but the server is configured to disallow HTTP access to that document. Contact the server maintainer to request that the configuration be changed to allow access.
`File _protected_ against access.`
  The server successfully parsed the request but the server is configured to restrict HTTP access to that document to authorized users only. Contact the server maintainer to request that the configuration be changed to allow access.
`Syntax error or malformed request`
  The server received a request that it deemed not in conformance with the HTTP protocol specification.
`Gateway function not available`
  The server successfully parsed the request but URL included a subsystem or host specification. Some servers response to such URLs by gatewaying, making the appropriate request to remote host/subsystem and relaying the response to the client. The Region 6 server does not support gatewaying.
`Invalid URL specified`
  The server failed to parse the URL.
`Method not supported by this server`
  The server successully parsed the request but the request method is not available on this server. The only methods required by the HTTP protocol specification are GET and HEAD.
`Search capability not enabled`
  The server successfully parse the request but the URL contains a SEARCH request (question mark) and the site's configuration file has not enabled this feature.
`Client does not accept data type`
  The server successfully parse the request but the requested object is not in a data format the client can process.