Problem migrating Yii2 project to host?

Question

Yii

everything works on the local server....
when I transferred it to the host, the ActiveRecord class stopped finding it, what's the problem? (Category.php file is already visible)
(in category.php class Category extends yii\db\ActiveRecord { changed to: class Category extends ActiveRecord { did not help)
here are the config/db.php settings

<?php

return [
    'class' => 'yii\db\Connection',
    'dsn' => 'mysql:host=hostt.zzz.com.ua;dbname=***********',  // название БД правильно указано
    'username' => '**********', // username тоже правильно указано
    'password' => '************',  // пароль тоже правильный
    'charset' => 'utf8',
];

what is the problem? how to solve?
host link: hostt.zzz.com.ua

Answer 1

Is the database server correct?

Answer 2

host=localhost?

Answer 3

"the class is no longer found" - did you transfer the framework itself, or just the project?