Error

PHP User Erroryii\base\ErrorException

Exception (Unknown Property) 'yii\base\UnknownPropertyException' with message 'Getting unknown property: app\modules\main\models\ForgotForm::username'

in /var/www/basic/vendor/yiisoft/yii2/base/Component.php:147

Stack trace:
#0 /var/www/basic/vendor/yiisoft/yii2/helpers/BaseHtml.php(2108): yii\base\Component->__get('username')
#1 /var/www/basic/vendor/yiisoft/yii2/helpers/BaseHtml.php(1287): yii\helpers\BaseHtml::getAttributeValue(Object(app\modules\main\models\ForgotForm), 'username')
#2 /var/www/basic/vendor/yiisoft/yii2/helpers/BaseHtml.php(1336): yii\helpers\BaseHtml::activeInput('text', Object(app\modules\main\models\ForgotForm), 'username', Array)
#3 /var/www/basic/vendor/yiisoft/yii2/widgets/ActiveField.php(395): yii\helpers\BaseHtml::activeTextInput(Object(app\modules\main\models\ForgotForm), 'username', Array)
#4 /var/www/basic/vendor/yiisoft/yii2/widgets/ActiveField.php(204): yii\widgets\ActiveField->textInput()
#5 /var/www/basic/vendor/yiisoft/yii2/widgets/ActiveField.php(176): yii\widgets\ActiveField->render()
#6 /var/www/basic/modules/main/views/user/forgot.php(19): yii\widgets\ActiveField->__toString()
#7 /var/www/basic/vendor/yiisoft/yii2/base/View.php(330): require('/var/www/basic/...')
#8 /var/www/basic/vendor/yiisoft/yii2/base/View.php(250): yii\base\View->renderPhpFile('/var/www/basic/...', Array)
#9 /var/www/basic/vendor/yiisoft/yii2/base/View.php(152): yii\base\View->renderFile('/var/www/basic/...', Array, Object(app\modules\main\controllers\UserController))
#10 /var/www/basic/vendor/yiisoft/yii2/base/Controller.php(381): yii\base\View->render('forgot', Array, Object(app\modules\main\controllers\UserController))
#11 /var/www/basic/modules/main/controllers/UserController.php(484): yii\base\Controller->render('forgot', Array)
#12 [internal function]: app\modules\main\controllers\UserController->actionForgot()
#13 /var/www/basic/vendor/yiisoft/yii2/base/InlineAction.php(57): call_user_func_array(Array, Array)
#14 /var/www/basic/vendor/yiisoft/yii2/base/Controller.php(156): yii\base\InlineAction->runWithParams(Array)
#15 /var/www/basic/vendor/yiisoft/yii2/base/Module.php(523): yii\base\Controller->runAction('forgot', Array)
#16 /var/www/basic/vendor/yiisoft/yii2/web/Application.php(102): yii\base\Module->runAction('main/user/forgo...', Array)
#17 /var/www/basic/vendor/yiisoft/yii2/base/Application.php(380): yii\web\Application->handleRequest(Object(yii\web\Request))
#18 /var/www/basic/web/index.php(37): yii\base\Application->run()
#19 {main}

$_SESSION = [
    '__flash' => [],
];