Add the below code into your functions.php file
function redirect_login_page()
{
$login_page = home_url('/login/'); //your redirect page link here
$page_viewed = basename($_SERVER['REQUEST_URI']);
if ($page_viewed == "wp-login.php" && $_SERVER['REQUEST_METHOD'] == 'GET') {
wp_redirect($login_page);
exit;
}
}
add_action('init', 'redirect_login_page');