Laravel 5.x error install "Class ExpectedQPair.php doesn't comply with psr-4 autoloading standard "

I took a project that is in laravel 5.6, and did the usual... clone, composer-update, and I got this error message.

image error

Class Egulias\EmailValidator\Exception\ExpectedQPair located in C:/laragon/www/spa-blog/vendor/egulias/email-validator/EmailValidator\Exception\ExpectingQPair.php does not comply with psr-4 autoloading standard. Skipping.
> Illuminate\Foundation\ComposerScripts::postAutoloadDump
> @php artisan package:discover


  [ErrorException]
  Undefined index: name


Script @php artisan package:discover handling the post-autoload-dump event returned with error code 1

I created the .env and generated the key, but it didn't allow me to run composer install or update either. I did the typical clean cache and dump-autoload, but I still can't move forward with the project.

What can be happening, what do you recommend me to do to solve this error?

Thank you in advance

via Chebli Mohamed