Try to login: ActiveQuery: Exception 'Error' with message 'Class name must be a valid object or a string'

[strtob]

I try to login an get the following error after press the submit button:

`

Exception 'Error' with message 'Class name must be a valid object or a string' 

in /opt/work/real-hive/vendor/yiisoft/yii2/db/ActiveQuery.php:324
Stack trace:
0 /opt/work/real-hive/vendor/yiisoft/yii2/db/Query.php(287): yii\db\ActiveQuery->createCommand()
1 /opt/work/real-hive/vendor/yiisoft/yii2/db/ActiveQuery.php(304): yii\db\Query->one()
2 /opt/work/real-hive/backend/components/modules/User/Form/LoginForm.php(179): yii\db\ActiveQuery->one()
3 /opt/work/real-hive/vendor/yiisoft/yii2/base/Model.php(351): backend\components\modules\User\Form\LoginForm->beforeValidate()
4 /opt/work/real-hive/vendor/yiisoft/yii2/widgets/ActiveForm.php(419): yii\base\Model->validate()
5 /opt/work/real-hive/backend/components/modules/User/Controller/SecurityController.php(136): yii\widgets\ActiveForm::validate()
6 [internal function]: backend\components\modules\User\Controller\SecurityController->actionLogin()
7 /opt/work/real-hive/vendor/yiisoft/yii2/base/InlineAction.php(57): call_user_func_array()
8 /opt/work/real-hive/vendor/yiisoft/yii2/base/Controller.php(178): yii\base\InlineAction->runWithParams()
9 /opt/work/real-hive/vendor/yiisoft/yii2/base/Module.php(552): yii\base\Controller->runAction()
10 /opt/work/real-hive/vendor/yiisoft/yii2/web/Application.php(103): yii\base\Module->runAction()
11 /opt/work/real-hive/vendor/yiisoft/yii2/base/Application.php(384): yii\web\Application->handleRequest()
12 /opt/work/real-hive/backend/web/index.php(18): yii\base\Application->run()
13 {main}

`

[maxxer]

Check the backend/components/modules/User/Form/LoginForm.php(179) file in your project

[strtob]

Thanks for your support! The problem was in my case that the Bootstrap class of the module needs to be set in the bootstrap array of the config file.