Im using iCloud password to log in and unlock the screen (System Preferences > Users and Groups). Yesterday iCloud password was changed using https://appleid.apple.com web-site (from my iPad). But my home iMac is still accepting old iCloud password to log in and unlock the screen. Why this happens? Looks like a security issue.
Restarting iMac and logging out and then back in to iCloud does not solves the issue.
Restarting iMac and logging out and then back in to iCloud does not solves the issue.