Fatal error: Uncaught Error: Interface "Symfony\Component\Security\Core\User\UserCheckerInterface" not found in /home/ldt/public_html/canvas/udoit/vendor/symfony/security-core/User/ChainUserChecker.php:14 Stack trace: #0 {main} thrown in /home/ldt/public_html/canvas/udoit/vendor/symfony/security-core/User/ChainUserChecker.php on line 14