Uncaught Error: Class "IlluminateFoundationApplication" not found

PHP Fatal Error:  Uncaught Error: Class "IlluminateFoundationApplication" not found in /home/prasaanth/myport/bootstrap/app.php:14
Stack trace: #0 /home/prasaanth/myport/artisan(20): require_once()
#1 {main} 
thrown in /home/prasaanth/myport/bootstrap/app.php on line

When I try to create a Laravel project, it is creating without a vendor file. Some other files are missing, and the  console is showing this error. Also, when I run the Artisan server, the same error is coming.

I had tried by creating new project and modify the composer

via Chebli Mohamed