Why is the module not included in Yii2?

Question

Yii

Created str module:
web.php

'modules' => [
        'str' => [
            'class' => 'app\modules\str\module',
            'layout' => 'main'
        ],
    ],

in the module there are several controllers, a bunch of models, views, etc. After transferring all the good stuff to the combat server, I get an error stating that this module was not found:

ReflectionException
Class app\modules\str\module does not exist

After disabling beautiful urls, xt-accessories, it got a little better, the error manifested itself better.
The question is how to debug this moment?
P.S. everything worked initially from under Windows, after the transfer to Linux, this began.

Answer 1

'modules' => [
        'str' => [
            'class' => 'app\modules\str\Module',
            'layout' => 'main'
        ],
    ],

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