use_authtok - When password changing enforce the module to set the new password to the one provided by a previously stacked password module use_authtok allows multiple pam modules to confirm a new password before it is accepted.
Solution
Edit or create the line use_authtok on the password stack's pam_unix.so module lines: /etc/pam.d/common-password:password required pam_unix.so use_authtok shadow sha512 /etc/pam.d/common-password-pc:password required pam_unix.so use_authtok shadow sha512