My Excel dashboard broke. Have a power query that pulls from a folder.... but getting "Unable to connect". I can browse and open in Explorer. Any ideas?

As a test: I simply started a blank Excel file > Get Data > From Folder - and pointed to the folder of xls files. Immediately met with the error.

The full error message: Unable to connect We encountered an error while trying to connect. Details: "We can't load data from this source due to its type of protection, or you may not have permission to extract data."

I have a Excel dashboard that has a couple power queries that aggregate xls files in a given folder. (ie: I will drop in a xls exported from another program, and the "dashboard" aggregates and graphs over time)

This month, I am getting problems. I deleted the file I just added - and it didn't change anything. It seems I'm getting some kind of permission issues, but I don't know why. I can browse/read/write the folder just fine.

Any idea where I need to resolve? Files are located on a network drive, but I have full read/write access in Explorer.