I eventually got this to work. I had originally downloaded the template and added some sheets to it in order to pull in my budgets using formulas. I also added columns to extract the GL numbers in order to run index matches. Then I resaved it with a new name. That workbook would not upload. I would go find it and hit next and nothing would happen.

What ended up working was to copy and paste the values from my version of the workbook into a newly downloaded template, saved without changing the name of the file. I don't know whether it was my extra sheets that I added, or the extra columns, or the formulas, or the new name I gave it... but something about the version I had saved wouldn't let it upload.