Can't crawl a site protected with Windows Auth.

Testing ability to log in using something like this in the URL field for a
crawl:

<http://username:password@www.domain.com/_layouts/15/Authenticate.aspx>

Getting back:

12:44:39 Error:  "Unauthorized" (401) at link
username:password@www.domain.com/_layouts/15/Authenticate.aspx (from
primary/primary)

The creds and domain work for sure (copy/pasted and tested) when using any
browser.

Thanks in advance!