How to make email notifications for errors and exceptions?

I try it, but this is not work. What is wrong?

PHP Code:

<?php
namespace App\Libraries;

use CodeIgniter\API\ResponseTrait;
use CodeIgniter\Exceptions\PageNotFoundException;
use CodeIgniter\HTTP\CLIRequest;
use CodeIgniter\HTTP\Exceptions\HTTPException;
use CodeIgniter\HTTP\IncomingRequest;
use CodeIgniter\HTTP\Response;
use Config\Exceptions as ExceptionsConfig;
use Config\Paths;
use ErrorException;
use Psr\Log\LogLevel;
use Throwable;

/**
* Exceptions manager
*/
class Exceptions extends Exceptions
{
    /**
    * Gathers the variables that will be made available to the view.
    */
    protected function collectVars(Throwable $exception, int $statusCode): array
    {
        $trace = $exception->getTrace();

        if ($this->config->sensitiveDataInTrace !== []) {
            $this->maskSensitiveData($trace, $this->config->sensitiveDataInTrace);
        }

        $return = [
            'title'  => get_class($exception),
            'type'    => get_class($exception),
            'code'    => $statusCode,
            'message' => $exception->getMessage(),
            'file'    => $exception->getFile(),
            'line'    => $exception->getLine(),
            'trace'  => $trace,
        ];
        
        //send email
        mail('[email protected]', 'test');

        return $return;
    }