Auto Routing Improved doesn't work for getIndex with parameters

I enabled Auto Routing improved and trying to follow the manuals. I want to add pagination to my clients list:

• /clients/13 - page 13
  
• /clients/1 - page 1
  

Code:

<?php

namespace App\Controllers;

class Clients extends BaseController
{
    public function getIndex($page = 1)
    {
      //TODO
      return view('clients/index', $data);
    }
}

However even with auto routing enabled /clients/13 results in error 404