Error: Class "Symfony\Component\DependencyInjection\Compiler\CheckExceptionOnInvalidReferenceBehaviorPass" not found in Symfony\Component\DependencyInjection\Compiler\PassConfig->__construct() (line 87 of /home/verkopenbelgie/public_html/vendor/symfony/dependency-injection/Compiler/PassConfig.php).
Symfony\Component\DependencyInjection\Compiler\PassConfig->__construct() (Line: 30) Symfony\Component\DependencyInjection\Compiler\Compiler->__construct() (Line: 477) Symfony\Component\DependencyInjection\ContainerBuilder->getCompiler() (Line: 457) Symfony\Component\DependencyInjection\ContainerBuilder->addCompilerPass() (Line: 60) Drupal\Core\CoreServiceProvider->register() (Line: 1305) Drupal\Core\DrupalKernel->compileContainer() (Line: 934) Drupal\Core\DrupalKernel->initializeContainer() (Line: 20) Drupal\Core\Installer\InstallerKernel->initializeContainer() (Line: 494) Drupal\Core\DrupalKernel->boot() (Line: 424) install_begin_request() (Line: 116) install_drupal() (Line: 48)
Symfony\Component\DependencyInjection\Exception\ServiceNotFoundException: You have requested a non-existent service "theme.manager". in Symfony\Component\DependencyInjection\ContainerBuilder->getDefinition() (line 992 of /home/verkopenbelgie/public_html/vendor/symfony/dependency-injection/ContainerBuilder.php).
Symfony\Component\DependencyInjection\ContainerBuilder->getDefinition() (Line: 568) Symfony\Component\DependencyInjection\ContainerBuilder->doGet() (Line: 531) Symfony\Component\DependencyInjection\ContainerBuilder->get() (Line: 649) Drupal::theme() (Line: 22) _drupal_maintenance_theme() (Line: 322) drupal_maintenance_theme() (Line: 1023) install_display_output() (Line: 271) _drupal_log_error() (Line: 182) _drupal_exception_handler()