If option is selected, by default WPLMS dows not allow to user to login unless they have logged out from other computer / session & gives a error message. But users rarely remember to logout their sessions.
Instead posting this code that will automatically logout the users previous session & login to current computer. This is achieved by storing the users latest session inside user meta fields & then comparing the current session with it.
PS You will logged out of admin on first time activation
if( !class_exists( 'WPSingleUserLoggin' ) )
{
class WPSingleUserLoggin
{
private $session_id;
function __construct()
{
if ( ! session_id() )
session_start();
$this->session_id = session_id();
add_action( 'init', array( $this, 'init' ) );
add_action( 'wp_login', array( $this, 'wp_login' ), 10, 2 );
}
function init()
{
if( ! is_user_logged_in() )
return;
$stored_sess_id = get_user_meta( get_current_user_id(), '_wp_single_user_hash', true );
if( $stored_sess_id != $this->session_id )
{
wp_logout();
wp_redirect( wp_login_url() );
exit;
}
}
function wp_login( $user_login, $user )
{
update_user_meta( $user->ID, '_wp_single_user_hash', $this->session_id );
return;
}
}
new WPSingleUserLoggin();
};
Original code link : https://benmay.org/wordpress/single-user-wordpress/