Fatal error: Uncaught Error: Class 'Zend\Diactoros\AbstractSerializer' not found in /home/kubalos2/public_html/testtestowy/vendor/zendframework/zend-diactoros/src/Response/Serializer.php:21 Stack trace: #0 {main} thrown in /home/kubalos2/public_html/testtestowy/vendor/zendframework/zend-diactoros/src/Response/Serializer.php on line 21