Why did the classes stop working?

Question

Yii

At some point, all models stopped working.

PHP Fatal Error – yii\base\ErrorException
Class 'common\models\LoginForm' not found

although the class was not touched at all and this is the situation with other models. It reaches the controller action (if you disable autologin, otherwise it swears even earlier for the lack of common/models/User) and there

public function actionIndex(){
        $bbb = Controller::className();
       return $bbb;
    }

no problem
here

public function actionIndex(){
        $bbb = User::className();
       return $bbb;
    }

mistake. And any model. I have no idea what could be the issue. At some point, everything fell apart. Where to dig?
I found out by typing that only common / models does not work, everything else is without problems, so I simply renamed the folder to common / model without "s". I write off for server monthly. The server is not mine, it's not enough to dig into the rights, so that he would live for a long time.

Answer 1

look at which path the autoloader is looking for the file and make sure that it is there the
autoloader is located in the vendor/yiisoft/yii2/BaseYii.php file, the autoload method