"Object of class couldn't be converted to string". How to solve ?

Dear Friends, I am looking a file upload pdf validation for limiting the number of pages in PDF uploaded . I tried many ways . But now get Exception as

    "message": "Object of class App\Rules\MaxPages could not be converted to string",
    "exception": "Error",
    "file": "C:\xampp\htdocs\ksit_mission\vendor\laravel\framework\src\Illuminate\Validation\ValidationRuleParser.php",
    "line": 134,

my AppServiceProvider class is

<?php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;
use Illuminate\Support\Facades\Validator;
use Smalot\PdfParser\Parser;
use App\Rules\MaxPages;
class AppServiceProvider extends ServiceProvider
{
    /**
     * Register any application services.
     */
    public function register(): void
    {
        //
    }

    /**
     * Bootstrap any application services.
     */
    public function boot(): void
    {
        // $this->app['validator']->extend('max_pages', function ($attribute, $value, $parameters, $validator) {
        //     $maxPages = $parameters[0];
        //     $rule = new MaxPages($maxPages);
        //     return $rule->passes($attribute, $value);
        // });
        Validator::extend('max_pages', function ($attribute, $value, $parameters, $validator) {
            if (!is_array($value)) {
                return false;
            }

            $maxPages = $parameters[0];

            foreach ($value as $file) {
                if (!$file->isValid()) {
                    return false;
                }

                $pdf = (new Parser())->parseFile($file->path());
                $numPages = count($pdf->getPages());
                if ($numPages > $maxPages) {
                    return false;
                }
            }

            return true;
        });

    }
}

1. MaxPages.php in app/Rules

<?php

namespace App\Rules;

use Illuminate\Validation\Rule;
use Illuminate\Support\Facades\Validator;
use Smalot\PdfParser\Parser;

class MaxPages extends Rule
{
    protected $maxPages;
    

    public function __construct($maxPages)
    {
        $this->maxPages = $maxPages;
    }


   
    public function passes($attribute, $value)
    {
        if (!is_array($value)) {
            return false;
            
        }

        foreach ($value as $file) {
            if (!$file->isValid()) {
                return false;
                
            }

            $pdf = (new Parser())->parseFile($file->path());
            $numPages = count($pdf->getPages());

            if ($numPages > $this->maxPages) {
                return false;
            }
        }

        return true;
    }

    public function message()
    {
        return "The :attribute must have a maximum of {$this->maxPages} pages.";
    }

    
}

call it in 6 places in controller as

'quali_upload.*' => ['required', 'file', 'mimes:pdf', 'max:2048', new MaxPages(3)],  // 2 times called
'upload_additional.*' => ['nullable','file','mimes:pdf','max:2048',new MaxPages(2)], // 2 times called
'uploadworkexperience.*' => ['nullable','mimes:pdf','max:2048',new MaxPages(1)],  // 2 times clalled 

with included in controller

use App\Rules\MaxPages;

Please help

Thanks

Anes P A