PHP Fatal error: Uncaught TypeError: rtrim() when trying to use db model in different controller

Need Help
1

hey why do I always get the following Error when i am trying to use the users db model in my mywebsockets controller…:

PHP Fatal error:  Uncaught TypeError: rtrim() expects parameter 1 to be string, null given in /var/www/html///vendor/cakephp/cakephp/src/Core/App.php:63
Stack trace:
#0 /var/www/html///vendor/cakephp/cakephp/src/Core/App.php(63): rtrim()
#1 /var/www/html///vendor/cakephp/cakephp/src/ORM/Locator/TableLocator.php(291): Cake\Core\App::className()
#2 /var/www/html///vendor/cakephp/cakephp/src/ORM/Locator/TableLocator.php(227): Cake\ORM\Locator\TableLocator->_getClassName()
#3 /var/www/html///vendor/cakephp/cakephp/src/Datasource/Locator/AbstractLocator.php(62): Cake\ORM\Locator\TableLocator->createInstance()
#4 /var/www/html///vendor/cakephp/cakephp/src/ORM/Locator/TableLocator.php(205): Cake\Datasource\Locator\AbstractLocator->get()
#5 /var/www/html///src/Controller/MywebsocketsController.php(280): Cake\ORM\Locator\TableLocator->get()
#6 /var/www/html///vendor/cbod in /var/www/html///vendor/cakephp/cakephp/src/Core/App.php on line 63

i tried it with many ways:

$this->loadModel('Users');
             
$usersTable = TableRegistry::getTableLocator()->get('Users');
$user = $usersTable->get($uid, [
 'contain' => ['Box'],
 ]);      

$usersTable = \Cake\ORM\TableRegistry::getTableLocator()->get('Users', [
'className' => 'App\Model\Table\UsersTable'
 ]);
                       
              
$usersTable = new UsersTable();
$user = $usersTable->get($uid, [
 'contain' => ['Box'],
]);

but i always get the same error.

my websocketscontroller looks like:

<?php
declare(strict_types=1);

namespace App\Model\Table;

use Cake\ORM\Query;
use Cake\ORM\RulesChecker;
use Cake\ORM\Table;
use Cake\Validation\Validator;

/**
 * Mywebsockets Model
 *
 * @property \App\Model\Table\UsersTable&\Cake\ORM\Association\BelongsTo $Users
 *
 * @method \App\Model\Entity\Mywebsocket newEmptyEntity()
 * @method \App\Model\Entity\Mywebsocket newEntity(array $data, array $options = [])
 * @method \App\Model\Entity\Mywebsocket[] newEntities(array $data, array $options = [])
 * @method \App\Model\Entity\Mywebsocket get($primaryKey, $options = [])
 * @method \App\Model\Entity\Mywebsocket findOrCreate($search, ?callable $callback = null, $options = [])
 * @method \App\Model\Entity\Mywebsocket patchEntity(\Cake\Datasource\EntityInterface $entity, array $data, array $options = [])
 * @method \App\Model\Entity\Mywebsocket[] patchEntities(iterable $entities, array $data, array $options = [])
 * @method \App\Model\Entity\Mywebsocket|false save(\Cake\Datasource\EntityInterface $entity, $options = [])
 * @method \App\Model\Entity\Mywebsocket saveOrFail(\Cake\Datasource\EntityInterface $entity, $options = [])
 * @method \App\Model\Entity\Mywebsocket[]|\Cake\Datasource\ResultSetInterface|false saveMany(iterable $entities, $options = [])
 * @method \App\Model\Entity\Mywebsocket[]|\Cake\Datasource\ResultSetInterface saveManyOrFail(iterable $entities, $options = [])
 * @method \App\Model\Entity\Mywebsocket[]|\Cake\Datasource\ResultSetInterface|false deleteMany(iterable $entities, $options = [])
 * @method \App\Model\Entity\Mywebsocket[]|\Cake\Datasource\ResultSetInterface deleteManyOrFail(iterable $entities, $options = [])
 */
class MywebsocketsTable extends Table
{
    /**
     * Initialize method
     *
     * @param array $config The configuration for the Table.
     * @return void
     */
    public function initialize(array $config): void
    {
        parent::initialize($config);

        $this->setTable('mywebsockets');
        $this->setDisplayField('id');
        $this->setPrimaryKey('id');

        $this->belongsTo('Users', [
            'foreignKey' => 'user_id',
        ]);
    }

    /**
     * Default validation rules.
     *
     * @param \Cake\Validation\Validator $validator Validator instance.
     * @return \Cake\Validation\Validator
     */
    public function validationDefault(Validator $validator): Validator
    {
        $validator
            ->integer('id')
            ->allowEmptyString('id', null, 'create');

        return $validator;
    }

    /**
     * Returns a rules checker object that will be used for validating
     * application integrity.
     *
     * @param \Cake\ORM\RulesChecker $rules The rules object to be modified.
     * @return \Cake\ORM\RulesChecker
     */
    public function buildRules(RulesChecker $rules): RulesChecker
    {
        $rules->add($rules->existsIn(['user_id'], 'Users'), ['errorField' => 'user_id']);

        return $rules;
    }
}

the websocketscontroller is started with:

<?php
// in src/WebSocket.php

namespace App;
use Ratchet\Server\IoServer;
use Ratchet\Http\HttpServer;
use Ratchet\WebSocket\WsServer;
use App\Controller\MywebsocketsController;



require dirname(__DIR__) . '/vendor/autoload.php'; // Autoload Composer packages



$webSocketServer = IoServer::factory(
    new HttpServer(
        new WsServer(
            new MywebsocketsController()
            )
        ),
    8080 // Port number
    );

$webSocketServer->run();

any idea? thx