500 Internal Server Error

Argument 2 passed to models\SingleEvent::__construct() must be an instance of DateTime, null given, called in /var/www/vhosts/school-bus.jp/production/app/mappers/EventMapper.php on line 208 (0)

#0 /var/www/vhosts/school-bus.jp/production/app/mappers/EventMapper.php(208): models\SingleEvent->__construct(Object(models\Event), NULL, NULL)
#1 /var/www/vhosts/school-bus.jp/production/app/controllers/EventsController.php(86): mappers\EventMapper->getFirstSingleEvent(Object(models\Event), Object(DateTime))
#2 /var/www/vhosts/school-bus.jp/production/vendor/mikecao/flight/flight/core/Dispatcher.php(167): controllers\EventsController->controllers\{closure}('77')
#3 /var/www/vhosts/school-bus.jp/production/vendor/mikecao/flight/flight/core/Dispatcher.php(143): flight\core\Dispatcher::callFunction(Object(Closure), Array)
#4 /var/www/vhosts/school-bus.jp/production/vendor/mikecao/flight/flight/Engine.php(311): flight\core\Dispatcher::execute(Object(Closure), Array)
#5 /var/www/vhosts/school-bus.jp/production/vendor/mikecao/flight/flight/core/Dispatcher.php(196): flight\Engine->_start()
#6 /var/www/vhosts/school-bus.jp/production/vendor/mikecao/flight/flight/core/Dispatcher.php(142): flight\core\Dispatcher::invokeMethod(Array, Array)
#7 /var/www/vhosts/school-bus.jp/production/vendor/mikecao/flight/flight/core/Dispatcher.php(48): flight\core\Dispatcher::execute(Array, Array)
#8 /var/www/vhosts/school-bus.jp/production/vendor/mikecao/flight/flight/Engine.php(64): flight\core\Dispatcher->run('start', Array)
#9 /var/www/vhosts/school-bus.jp/production/vendor/mikecao/flight/flight/core/Dispatcher.php(196): flight\Engine->__call('start', Array)
#10 /var/www/vhosts/school-bus.jp/production/vendor/mikecao/flight/flight/Flight.php(76): flight\core\Dispatcher::invokeMethod(Array, Array)
#11 /var/www/vhosts/school-bus.jp/production/app/web/Base.php(9): Flight::__callStatic('start', Array)
#12 /var/www/vhosts/school-bus.jp/production/app/shortcuts.php(257): web\Base->run()
#13 /var/www/vhosts/school-bus.jp/production/public/index.php(7): web()
#14 {main}