Is Zotero still functioning?
I have been unable to add book references since September 2020. Is it the sites I am using? They include a university library, World cat and Amazon. A pop up appears but then no new titles is added to my library folder. I have perhaps a wrong setting?
https://www.zotero.org/support/troubleshooting_translator_issues and report the information in the last bullet point if the previous ones don't fix this for you
Because of that, every time you've saved with Zotero open and then try to save with it closed, you'll get prompted to reopen it and need to specifically opt in to saving to the online library. There's no way to change that. You can opt in to that, but it's not the recommended way of using Zotero. Until you reopen Zotero, you won't get prompted again.
When you do save to the Zotero program, you'll need to have set up syncing to see your data online, and then that will happen automatically within a few seconds of saving.
But again, for any significant work with Zotero, we strongly recommend primarily using the Zotero program.