Fatal error: Uncaught Error: Class 'Symfony\Component\Validator\ConstraintValidator' not found in C:\Apache24\htdocs\InvoiceTracking\vendor\symfony\validator\Constraints\SequentiallyValidator.php:21 Stack trace: #0 {main} thrown in C:\Apache24\htdocs\InvoiceTracking\vendor\symfony\validator\Constraints\SequentiallyValidator.php on line 21