Tips for troubleshooting "Book conversion failed" error message?
I've never seen it before, and I can't think of anything I'm doing that's different from what I've done hundreds of times before.

It also gave me this spreadsheet popup:
Obviously it could be a problem within Kindle Previewer, but I thought I'd check here first. I'll try again with other files I know have converted OK in the past, but not tonight...time to throw in the towel and admit I'm not going to finish this project this week!
I'm using Windows 10, InDesign 14.0.2 x64, and Kindle Previewer 3.31.0.
