iis-status-causes.txt

200 - Success. This status code indicates that IIS has successfully processed the request.
206 - Partial Content. This indicates that a file has been partially downloaded. It can enable resuming of interrupted downloads, or split a download into multiple concurrent streams.
207 - Multi-Status (WebDav). This comes before an XML message that can contain several separate response codes, depending on how many sub-requests were made.
301 - Moved Permanently. This and all future requests should be directed to the given URI.
302 - Found. This is frequently represented as Object Moved for forms based authentication. The requested resource resides temporarily under a different URI. Because the redirection might be altered occasionally, the client should continue to use the Request-URI for future requests. This response is only cacheable if indicated by a Cache-Control or Expires header field.
304 - Not Modified. The client requests a document that is already in its cache and the document has not been modified since it was cached. The client uses the cached copy of the document, instead of downloading it from the erver.
401.1 and 401.2 - Logon failed. The logon attempt is unsuccessful because a user name or a password is not valid, or because there is a problem with the system configuration.
401.3 - Unauthorized due to ACL on resource. This indicates a problem with NTFS permissions. This error may occur even if the permissions are correct for the file that you are trying to access. For example, you see this error if the IUSR account does not have access to the C:\Winnt\System32\Inetsrv directory.
403 - Forbidden. You can receive this generic 403 status code if the Web site has no default document set, and the site is not set to allow Directory Browsing. 
403.1 - Execute access forbidden. The following are two common causes of this error message: You do not have enough Execute permissions. For example, you may receive this error message if you try to access an ASP page in a directory where permissions are set to None, or you try to execute a CGI script in a directory with Scripts Only permissions. To modify the Execute permissions, right-click the directory in Microsoft Management Console (MMC), click Properties, click the Directory tab, and make sure that the Execute Permissions setting is appropriate for the content that you are trying to access.  The script mapping for the file type that you are trying to execute is not set up to recognize the verb that you are using (for example, GET or POST). To verify this, right-click the directory in Microsoft Management Console, click Properties, click the Directory tab, click Configuration, and verify that the script mapping for the appropriate file type is set up to allow the verb that you are using.
403.2 - Read access forbidden. Verify that you have set up IIS to allow Read access to the directory. Also, if you are using a default document, verify that the document exists.
403.3 - Write access forbidden. Verify that the IIS permissions and the NTFS permissions are set up to grant Write access to the directory.
403.4 - SSL required. Disable the Require secure channel option, or use HTTPS instead of HTTP to access the page.
403.5 - SSL 128 required. Disable the Require 128-bit encryption option, or use a browser that supports 128-bit encryption to go to the page.
403.6 - IP address rejected. You have configured the server to deny access to your current IP address. 
403.7 - Client certificate required. You have configured the server to require a certificate for client authentication, but you do not have a valid client certificate installed.
403.8 - Site access denied. You have set up a domain name restriction for the domain that you are using to access the server.
403.9 - Too many users. The number of users who are connected to the server exceeds the connection limit that you have set. 
403.12 - Mapper denied access. The page that you want to access requires a client certificate. However, the user ID that is mapped to the client certificate has been denied access to the file.
404 - Not found. This error may occur if the file that you are trying to access has been moved or deleted. It can also occur if you try to access a file that has a restricted file name extension after you install the URLScan tool. You will see Rejected by URLScan" in the w3svc log files after you install the URLScan tool. In this case, you see "Rejected by URLScan" in the log file entry for that request. 
404.1 - Web Site not accessible on the requested port. This error indicates that the Web site you are trying to access has an IP address that does not accept requests for the port on which this request came.
404.2 - Lockdown policy prevents this request. In IIS 6.0, this indicates that the request has been prohibited in the Web Service Extensions list.
404.3 - MIME Map policy prevents this request. This problem occurs if the following conditions are true: The handler mapping for the requested file name extension is not configured.  The appropriate MIME type is not configured for the Web site or for the application.
405 - Method not allowed. This error can occur when a client sends an HTTP request to the server that is running IIS, and the request contains an HTTP verb that the server does not recognize. To resolve the issue, make sure that the clients request uses an HTTP verb that is compliant with the HTTP rfc. See the "References" section for information about the HTTP rfc.
500 - Internal server error. You see this error message for many server-side errors. Your event viewer logs may contain more information about why this error occurs. Additionally, you can disable friendly HTTP error messages to receive a detailed description of the error. 
500.12 - Application restarting. This indicates that you tried to load an ASP page while IIS was restarting the application. This message should disappear when you refresh the page. If you refresh the page and the message appears again, it may be caused by antivirus software that is scanning your Global.asa file. 
500-100.ASP - ASP error. You receive this error message when you try to load an ASP page that has errors in the code. To obtain more specific information about the error, disable friendly HTTP error messages. By default, this error is only enabled on the default Web site.
502 - Bad gateway. You receive this error message when you try to run a CGI script that does not return a valid set of HTTP headers. To resolve the issue, you have to debug the CGI application to determine why it passed invalid HTTP information to IIS.
503 - Service Unavailable. Beginning in IIS 6, the kernel-mode Http.sys component produces an HTTP 503 status.
500.19. You receive this error when the XML metabase contains invalid configuration information for the content type that you are trying to access. To resolve this issue, remove or correct the invalid configuration. This problem typically indicates a problem in the ScriptMap metabase key.