For one, certain OAUTH errors will trigger this. Another scenario can be created by removing a resource controller in the API (server) then creating a new object of its type on the client. At this point, the $config variable will hold the following:

```
array(8) {
  'code' =>
  int(404)
  'type' =>
  string(14) "CHttpException"
  'errorCode' =>
  int(0)
  'message' =>
  string(55) "Unable to resolve the request "productVariant/options"."
  'file' =>
  string(61) "/vagrant/vendor/yiisoft/yii/framework/web/CWebApplication.php"
  'line' =>
  int(286)
  'trace' =>
  string(287) "#0 /vagrant/vendor/yiisoft/yii/framework/web/CWebApplication.php(141): CWebApplication->runController(\'productVariant/...\')\n#1 /vagrant/vendor/yiisoft/yii/framework/base/CApplication.php(180): CWebApplication->processRequest()\n#2 /vagrant/www/index.php(14): CApplication->run()\n#3 {main}"
  'traces' =>
  array(3) {
    [0] =>
    array(6) {
      'file' =>
      string(61) "/vagrant/vendor/yiisoft/yii/framework/web/CWebApplication.php"
      'line' =>
      int(141)
      'function' =>
      string(13) "runController"
      'class' =>
      string(15) "CWebApplication"
      'type' =>
      string(2) "->"
      'args' =>
      array(1) {
        [0] =>
        string(22) "productVariant/options"
      }
    }
    [1] =>
    array(6) {
      'file' =>
      string(59) "/vagrant/vendor/yiisoft/yii/framework/base/CApplication.php"
      'line' =>
      int(180)
      'function' =>
      string(14) "processRequest"
      'class' =>
      string(15) "CWebApplication"
      'type' =>
      string(2) "->"
      'args' =>
      array(0) {
      }
    }
    [2] =>
    array(6) {
      'file' =>
      string(22) "/vagrant/www/index.php"
      'line' =>
      int(14)
      'function' =>
      string(3) "run"
      'class' =>
      string(12) "CApplication"
      'type' =>
      string(2) "->"
      'args' =>
      array(0) {
      }
    }
  }
}
```

In normal circumstances $config will hold what appears to be a resource object in array form.