IOError: [Errno 1] Operation not permitted: ‘/etc/pam.d/system-auth’ – Linux server 7 to 8 upgrade

After error IOError: [Errno 1] Operation not permitted: '/etc/pam.d/system-auth' , the server drops to emergency mode.

To resolve this issue, Unset the immutable bit on system-auth-ac [This is symlink to /etc/pam.d/password-auth] with chattr -i /etc/pam.d/system-auth-ac