How to configure URL token in yii2 rest UrlRule - yii2

Question

I just created a yii2 rest API but some of the endpoint created are not working as expected.
when i do http://localhost/v1/countries I get a response but when i do http://localhost/v1/countries/AU i get a 404 error. I think the problem is with the token but i don't know how to fix this. Any help would be appreciated
<?php
namespace api\modules\v1\controllers;
class CountryController extends \yii\rest\ActiveController
{
public $modelClass = 'api\modules\v1\models\Country';
}
<?php
namespace api\modules\v1\models;
/**
* This is the model class for table "country".
*
* #property string $code
* #property string $name
* #property int $population
*/
class Country extends \yii\db\ActiveRecord
{
/**
* {#inheritdoc}
*/
public static function tableName()
{
return 'country';
}
public static function primaryKey() {
return ['code'];
}
/**
* {#inheritdoc}
*/
public function rules()
{
return [
[['code', 'name'], 'required'],
[['population'], 'integer'],
[['code'], 'string', 'max' => 2],
[['name'], 'string', 'max' => 52],
[['code'], 'unique'],
];
}
/**
* {#inheritdoc}
*/
public function attributeLabels()
{
return [
'code' => 'Code',
'name' => 'Name',
'population' => 'Population',
];
}
}
config file
'urlManager' => [
'enablePrettyUrl' => true,
'showScriptName' => false,
'enableStrictParsing' => true,
'rules' => [
['class' => 'yii\rest\UrlRule',
'controller' => ['v1/default', 'v1/country'],
'tokens' => [ '{id}' => 'id:\\w+' ],
//'pluralize'=>false,
'extraPatterns' => [
'GET,POST,PUT index' => 'index',
],
],
],
],
GET /countries: working
HEAD /countries: return status 200 empty message
POST /countries: working
GET /countries/AU: not working 404 error
HEAD /countries/AU: not working 404 error
PATCH /countries/AU: not working 404 error
PUT /countries/AU: not working 404 error
DELETE /countries/AU: not working 404 error
OPTIONS /countries: return status 200 (null)
OPTIONS /countries/AU: not working 404 error