Summary

When your Web Access virtual directory is configured to use integrated Windows authentication, if you attempt to load Web Access Scanning from a computer that is not on the same network, you may receive the following error message:

Could not establish connection.
Reason: An error occurred while sending a request to the server.
Reason: Unknown IIS error 401[16005].

Cause

When your Web Access virtual directory is configured to use integrated Windows authentication, you will be prompted to manually provide Windows credentials when you attempt to log in to Web Access from a computer that is not on the same domain. However, this feature is not available in Web Access Scanning. When you attempt to load Web Access Scanning from outside the domain, it does not prompt you to manually specify authentication information and the log in process fails.

Workaround

This issue does not occur when accessing Web Access and Web Access Scanning from within the network. If you must access Web Access Scanning from off the network, you can create another IIS virtual directory that is configured for anonymous access.