Fatal error: Uncaught Error: Class 'Zend\Http\Header\AbstractDate' not found in /home/app/htdocs/ninja/vendor/zendframework/zend-http/src/Header/IfModifiedSince.php:15 Stack trace: #0 {main} thrown in /home/app/htdocs/ninja/vendor/zendframework/zend-http/src/Header/IfModifiedSince.php on line 15