DUA Does Not Download Files from the Web Server

The Device Update (.dup) file runs, but files are not downloaded from the server.

The following list shows different events, logs, and settings that you should inspect:

Use the Event Viewer for the DUA service to see the relevant WinHTTP error code. From a command line, type eventvwr.

Use the error code that is listed in the event viewer to troubleshoot your connection to the Web server. If DUA is unable to connect to the server, the error code will be a WinHTTP error code. More information about WinHTTP error codes can be found at this Microsoft Web site.
Review your Web server's access logs to determine the error type that was returned to the client. Typically, 404 errors denote a problem accessing the file, 403 errors denote client authorization errors.
Verify that the account that DUA is using to access the files on the Web server has the appropriate access permissions to the files on the Web server.
In your device update script, verify that the files are located in a path relative to the directory of the root of the Web server, and not the location of the Device Update Program file.
Verify that the MIME settings of your Web server are configured to host the file extensions you are having trouble downloading.

Additional resources