I've had a bedtime routine set up for a long while that would turn off my lights, turn down my speaker, and play a specific audiobook from my Google play books library. I used a custom action to specify the audiobook and have it stop playing after about 30 minutes.
After a few months I changed it to a different book and it still worked fine. Now I'm trying to change it to a new book and after it runs through everything else in the routine, I get the "I'm sorry I don't understand" response when it tries to play the book.
I've tried changing it to about 5 different titles to test it, but the only one that will play is the most recent book that worked. It's as if it opens my play library and sees only a single book. I even created a new routine to see if that might work and it's the same thing.
Any idea why home suddenly can't recognize my play books library?
This is not the experience we wanted you to have, let me help you. A few things: which Nest speakers are we working with? When did your issue begin? Were there any recent changes made?
It would help a lot if you could do a sequential reboot first:
Once done, give a direct command by saying "Hey, Google! Read <audiobook title>" from the library. For more information about playing audiobooks, see this guide.
If the issue persists, you can edit or delete/recreate a routine with the audiobook in it. Follow the steps here.
Let me know how it goes.