Unable to change the password Error:User not known to the underlying authentication module

Applies To:

Oracle Cloud Infrastructure - Version N/A and later

Linux x86-64 on Oracle Public Cloud

Symptoms:

Unable to change the passwd of root user

root@test# passwd root
Changing password for user root
Current password: 
New password: 
Retype new password: 
passwd: User not known to the underlying authentication module
Passwd and shadow have correct file ownership/permission and SELinux file label

root@test# ls -alZ passwd shadow
-rw-r--r--. 1 root root system_u:object_r:passwd_file_t:s0 1575 June 6 19:35 passwd
----------. 1 root root system_u:object_r:shadow_t:s0       911 Jun 6 20:55 shadow

root@test# lsattr passwd shadow