Can 401 errors in HTTP:// or HTTPS:// be considered valid?

I'm building URL monitors for a client for both HTTP:// and HTTPS:// with credentials that are not on the server, so of course, they are failing with a "The remote server returned an error: (401) Unauthorized" error.  The client says that they can only assign a single instance to a specific user in the Servlet Exec config files.  Their point was that if they get a 401 error, then that means the server is responding by rejecting the credentials given in the monitor.  So is '401' an error that is hardcoded in the Component Monitors for HTTP:// or HTTPS://?  I see "Ignore CA Errors" and "Ignore CN Errors", but not sure if they are specific to 401.

Thanks,

Steve B.