"Problem with defaults entries" emails being sent to admin email

Symptoms

When a user uses the sudo command, an email is sent to the admin email (typically root@hostname) with the notification that there is a "Problem with defaults entries"

Description 

When SSSD is installed, it adds the following configuration line to the file /etc/nsswitch.conf:

sudoers: files sss

According to the following Red Hat bug report: https://bugzilla.redhat.com/show_bug.cgi?id=879633

When sudo is used with sssd and a local user runs sudo, an e-mail is sent to administrator, because sssd does not support sudo rules for local users. It is not an error, only noise.

This may be most commonly seen when SSSD and the WP-Toolkit are installed on the same server with the following notification:

sudo: wp-toolkit : problem with defaults entries ; TTY=unknown ; PWD=/usr/local/cpanel/3rdparty/wp-toolkit/scripts ; USER=root ;

Workaround

Edit the file /etc/nsswitch.conf and find the following line:

sudoers: files sss

Edit this line and remove the "sss" entry:

sudoers: files