Wordpress login restriction depends on user role.

function.php

<?php add_filter( 'wp_authenticate_user', 'restrict_login', 10, 2 );
function restrict_login( $user, $password ) {
	if ( is_wp_error( $user ) ) {
		return $user;
	}

	$roles   = array('administrator','subscriber');
	//$roles[] = 'administrator';
	if (array_reduce( $roles, function ( $allowed, $role ) use ( $user ) {
			return $allowed || user_can( $user, $role );
		}, false )
	) {
		return $user;
	}

	return new WP_Error( 'auth', __( 'Access denied!', 'restrict-role-login' ) );
}