You changed your password and still cannot sign in

Why a new password sometimes fails right after you set it.

Changing your password can lock the mailbox for a short time. Every device still trying the old password counts as a failed attempt, and enough of those trip the lock.

So the usual cause is a locked mailbox rather than a wrong password. See your mailbox is locked, which explains how to wait out the lock and then update your devices one at a time.