Fatal error: Uncaught Error: Class "Symfony\Component\String\AbstractString" not found in D:\Apache24\www\api.print.nxytec.cn\back\vendor\symfony\string\AbstractUnicodeString.php:29 Stack trace: #0 {main} thrown in D:\Apache24\www\api.print.nxytec.cn\back\vendor\symfony\string\AbstractUnicodeString.php on line 29