Users getting message "passwd: Authentication token manipulation error" when changing their passwords on Red Hat Enterprise Linux

Issue

• Users not able to change password using passwd and getting error as "passwd: Authentication token manipulation error"
• Some users are not able to change their own password:

# su - testuser
$ passwd 
Changing password for user testuser
Changing password for testuser

(current) UNIX password: 
passwd: Authentication token manipulation error 

I am trying to change a user password and neither root can perform this operation:

# passwd testuser
Changing password for user testuser.
passwd: Authentication token manipulation error

root can change passwords for local users. Newly added users can also change their password, however existing users can not change their passwords.