Fatal error: Uncaught Error: Class 'Magento\Framework\Serialize\Serializer\Json' not found in /app/vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php:93 Stack trace: #0 /app/vendor/magento/framework/ObjectManager/Factory/Compiled.php(88): Magento\Framework\ObjectManager\Factory\AbstractFactory->createObject('Magento\\Framewo...', Array) #1 /app/vendor/magento/framework/ObjectManager/ObjectManager.php(71): Magento\Framework\ObjectManager\Factory\Compiled->create('Magento\\Framewo...') #2 /app/vendor/amasty/module-improved-layered-navigation-page/Model/ResourceModel/PageRepository.php(141): Magento\Framework\ObjectManager\ObjectManager->get('Magento\\Framewo...') #3 /app/vendor/amasty/module-improved-layered-navigation-page/Model/ResourceModel/PageRepository.php(185): Amasty\ShopbyPage\Model\ResourceModel\PageRepository->normalizeInputData(Array) #4 /app/vendor/amasty/module-improved-layered-navigation-page/Model/ResourceModel/PageRepository.php(217): Amasty\ShopbyPage\Model\ResourceModel\PageRepository->get in /app/vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php on line 93