Не совершает вывод ошибки для валидации в Yii2?

public $contact;

    public function rules()
    {
        return [
            [['contact'], 'required', 'message' => Yii::t('app', 'The field does not have to be empty!')],
            [['contact'], 'string', 'min' => 4, 'message' => Yii::t('app', 'Contact should contain at least 4 characters.')],
        ];
    }

[['contact'], 'string', 'min' => 4, 'message' => Yii::t('app', 'Contact should contain at least 4 characters.')],