Fatal error: Uncaught Error: Class "Slim\Psr7\Message" not found in C:\xampp\htdocs\backend\vendor\slim\psr7\tests\Mocks\MessageStub.php:17 Stack trace: #0 {main} thrown in C:\xampp\htdocs\backend\vendor\slim\psr7\tests\Mocks\MessageStub.php on line 17