Looks like Amazon is retiring the Goodreads API, which just another step towards basically abandoning Goodreads and folding it into some other Amazon service I guess: https://joealcorn.co.uk/blog/2020/goodreads-retiring-API
My advice? Get off Goodreads while you still can (ie export your content) and move over to StoryGraph: https://beta.thestorygraph.com
A black-owned startup finally developing a viable alternative to Goodreads. Fuck yeah!
(Why not LibraryThings? Because, guess what.. it’s also owned by Amazon!)