401 error. Can't access dashboard

Hello – I’ve been working on a basic site (currently located at https://williamsonconsultingservice.com/_wp/).

Now when I try to access my login page (https://williamsonconsultingservice.com/_wp/wp-admin/)I receive a “401 Unauthorized” error in both FireFox and IE. The rest of the text of the error is

This server could not verify that you are authorized to access the document requested. Either you supplied the wrong credentials (e.g., bad password), or your browser doesn’t understand how to supply the credentials required.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

And the URL that appears in the browser is https://williamsonconsultingservice.com/_wp/wp-login.php?redirect_to=http%3A%2F%2Fwilliamsonconsultingservice.com%2F_wp%2Fwp-admin%2F&reauth=1

I did some searching, and found other 401 errors, but most seemed tied to a plugin, that when deleted, took care of it. I didn’t add any plugins before this started happening.

Thanks for any help and I’m happy to provide more info if it is needed!
Chris