Why is the permissions error displayed without styles?

Question

Yii

It is not clear when and because of what the error styles are no longer displayed

Answer 1

You have a problem in the settings of access rules for different actions of the controller.
You must either exclude the "error" action from the check, or specify it explicitly.
Something like this

return [
        'access' => [
            'class' => \yii\filters\AccessControl::className(),
            'except' => ['error'], // или так
            'rules' => [
              // или так
                [
                        'actions' => ['index', 'error'],
                        'allow' => true,
                 ],
            ],
        ],
    ];