Book Module – Blurb no longer an option?

So, I thought I'd give the LR Classic Book Module a try again after a few years of not using it. Well, with macOS Sonoma 14.1, and Lightroom Classic 13.1 on an Apple M1, I can neither get an estimated price (the "learn more" dialog that replaces it just takes me to ther Blurb general Lightroom (CC and Classic) info page here: https://www.blurb.com/lightroom) Neither will the app let me "Send book to Blurb" (button is greyed out). I tried every possible Blurb option in the LRC dialog, but nothing worked. If I choose output to PDF, evertyhing works as expected.

What's going on here?!?

– Hans Rupert