BackpackForLaravel/Lobby

hi everyone, please a question. I'm using 'relationship' field and while records are appearing when I load the page, modifications aren't being saved (adding new records nor removing). I have the following on my CrudController:

protected function fetchUser()
{
    // return $this->fetch(\App\Models\User::class);
    return $this->fetch([
        'name' => 'users',
        'model' => \App\Models\User::class, // required
        'searchable_attributes' => ['last_name', 'first_name', 'email'],
        'paginate' => 10, // items to show per page
        // 'query' => function($model) {
        //     return $model->active();
        // } // to filter the results that

    ]);

and the relationship config:

        [   // relationship
            'type' => "relationship",
            'name' => 'users', // the method on your model that defines the relationship
            'ajax' => true,

            // OPTIONALS:
            'label' => "Category",
            'attribute' => "email", // foreign key attribute that is shown to user (identifiable attribute)
            'entity' => 'users', // the method that defines the relationship in your Model
            'model' => "App\Models\User", // foreign key Eloquent model
            'placeholder' => "Select users", // placeholder for the select2 input

            // AJAX OPTIONALS:
            'data_source' => url("client/fetch/user"), // url to controller search function (with /{id} should return model)
            'minimum_input_length' => 2, // minimum characters to type before querying results
            // 'dependencies'         => [‘category’], // when a dependency changes, this select2 is reset to null
            // 'include_all_form_fields'  => false, // optional - only send the current field through AJAX (for a smaller payload if you're not using multiple chained select2s)
         ],

please any ideas what to check here? It's a 1-N relationship from client-> users, hope that's not causing issues.