Fatal error: Uncaught Error: Class "PHPUnit\Framework\TestCase" not found in /home/mainwebsite/public_html/vendor/symfony/mailer/Test/AbstractTransportFactoryTestCase.php:21 Stack trace: #0 {main} thrown in /home/mainwebsite/public_html/vendor/symfony/mailer/Test/AbstractTransportFactoryTestCase.php on line 21