Why is the empty POST in YII2 after reinstallation?

We developed our own api for mobile applications, which works on the basis of post requests, but after reinstalling the project on a new server, Yii :: $ app-> request-> post () always returns an empty value. At the same time, Yii :: $ app-> request-> getRawBody () contains a value, but I would not want to rewrite all api.

Tell me what could be the problem and which way to dig? Thanks in advance.

Sending through a mobile application or post through RestClient PHPStorm. Returns emptiness always.

public function behaviors()
{
    return [
        'access' => [
            'class' => AccessControl::class,
            'only' => ['logout', 'signup'],
            'rules' => [
                [
                    'actions' => ['login'],
                    'allow' => true,
                    'roles' => ['?'],
                ],
                [
                    'actions' => ['login'],
                    'allow' => true,
                    'roles' => ['@'],
                ],
            ],
        ],
        'verbs' => [
            'class' => VerbFilter::class,
            'actions' => [
                'login' => ['post', 'get'],
                'token' => ['post', 'get'],
                'logout' => ['post', 'get'],
            ],
        ],
    ];
}

public function beforeAction($action) {
    $this->enableCsrfValidation = false;
    return parent::beforeAction($action);
}

public function actionLogin()
{
    return Yii::$app->request->post("username");
}