401 Exception When Indexing Site?

Hi all - 

I'm getting this error for every piece of content in my site that I try to index using Episerver Find's index job:

An exception occurred while indexing content [Link ###] [GUID ##############] [Type TYPE] [Name NAME]:
The remote server returned an error: (401) Unauthorized. Unauthorized (see log for more information)

1. I triple-checked all my configs... they seem right, in fact I followed the directions here
2. This site is using CMS + Commerce, and I installed the 3 NuGet packages listed here
3. I've never indexed the site before - brand new installation / first time indexing

Has anyone else dealt with this?