Troubleshooting Epub won't open on Kindle Scribe Colorsoft

[Fledchen]

I'm having trouble downloading/opening an epub file I uploaded using send-to-kindle. It works fine on my Kindle for Android app on my phone and on my Kindle Paperwhite Signature Edition 12 Generation. When I tap on it, it initializes the download, gets as far as 1%, and then as far as I can tell the download manager crashes because the thumbnail goes back to just showing the file name instead of the cover or first page of the file. I've tried rebooting the Scribe but it didn't fix anything. Any ideas why it's choking on this file?