Troubleshooting Can't open Scribe notebooks in read.amazon.com

This has worked in the past for me. I'm trying to open my notebooks from read.amazon.com. The folders and icons display correctly, but, when I try to open a notebook, I receive the following error message: "Sorry, your notebook couldn't be opened. Please try again."

I've tried on multiple notebooks, to no avail. I'm on a MacBook Pro running Ventura 13.4 and using Safari. I've been able to open notebooks from this machine before.

Any troubleshooting tips?