Ups! An error has occurred!

The following hints should help you.

Entity has to be managed or scheduled for removal for single computation Shopware\Models\Tracking\Banner@00000000758f08930000000003776b86 in vendor/doctrine/orm/lib/Doctrine/ORM/UnitOfWork.php on line 475

Stack trace:

#0 vendor/doctrine/orm/lib/Doctrine/ORM/UnitOfWork.php(342): Doctrine\ORM\UnitOfWork->computeSingleEntityChangeSet(Object(Shopware\Models\Tracking\Banner))
#1 vendor/doctrine/orm/lib/Doctrine/ORM/EntityManager.php(356): Doctrine\ORM\UnitOfWork->commit(Object(Shopware\Models\Tracking\Banner))
#2 engine/Shopware/Controllers/Frontend/Tracking.php(73): Doctrine\ORM\EntityManager->flush(Object(Shopware\Models\Tracking\Banner))
#3 engine/Library/Enlight/Controller/Action.php(193): Shopware_Controllers_Frontend_Tracking->countBannerClickAction()
#4 engine/Library/Enlight/Controller/Dispatcher/Default.php(549): Enlight_Controller_Action->dispatch('countBannerClic...')
#5 engine/Library/Enlight/Controller/Front.php(222): Enlight_Controller_Dispatcher_Default->dispatch(Object(Enlight_Controller_Request_RequestHttp), Object(Enlight_Controller_Response_ResponseHttp))
#6 engine/Shopware/Kernel.php(215): Enlight_Controller_Front->dispatch()
#7 vendor/symfony/http-kernel/HttpCache/HttpCache.php(486): Shopware\Kernel->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#8 engine/Shopware/Components/HttpCache/AppCache.php(268): Symfony\Component\HttpKernel\HttpCache\HttpCache->forward(Object(Symfony\Component\HttpFoundation\Request), true, NULL)
#9 vendor/symfony/http-kernel/HttpCache/HttpCache.php(443): Shopware\Components\HttpCache\AppCache->forward(Object(Symfony\Component\HttpFoundation\Request), true)
#10 vendor/symfony/http-kernel/HttpCache/HttpCache.php(339): Symfony\Component\HttpKernel\HttpCache\HttpCache->fetch(Object(Symfony\Component\HttpFoundation\Request), true)
#11 engine/Shopware/Components/HttpCache/AppCache.php(189): Symfony\Component\HttpKernel\HttpCache\HttpCache->lookup(Object(Symfony\Component\HttpFoundation\Request), true)
#12 vendor/symfony/http-kernel/HttpCache/HttpCache.php(205): Shopware\Components\HttpCache\AppCache->lookup(Object(Symfony\Component\HttpFoundation\Request), true)
#13 engine/Shopware/Components/HttpCache/AppCache.php(116): Symfony\Component\HttpKernel\HttpCache\HttpCache->handle(Object(Symfony\Component\HttpFoundation\Request), 1, true)
#14 shopware.php(122): Shopware\Components\HttpCache\AppCache->handle(Object(Symfony\Component\HttpFoundation\Request))
#15 {main}