Sudo: PAM authentication error: User not known to the underlying authentication module

Hi Team,

I attempted to configure LDAP in SUSE Enterprise Linux; however, after the configuration, I am unable to switch to the root user. It displays the following error.

admin@apcinwrappd01:~> sudo su -
[sudo] password for admin:
sudo: PAM authentication error: User not known to the underlying authentication module

Any help will be appreciated

Regards:
Kumar