My iPad and Mac started complaining this morning that my password for Zoho account does not work, and they cannot connect to my accounts. These systems use an application-specific password I generated for use with IMAP on 2021-11-30, over three months ago. That app password is still listed in https://accounts.zoho.com/home#security/app_password and I recorded the password in my password manager, so I still know what it was when I set it up.

Why is this app password no longer working? Why is it that every few months my app passwords always stop working in this same way? Does Zoho "expire" app passwords or invalidate them in some way?

How can I resolve this situation without having to remove these accounts on my Mac and iPad and recreate them every few months?