Fatal error: Uncaught Error: Class "Symfony\Component\Mime\Encoder\Base64Encoder" not found in D:\Apache24\www\qilu\back-end\vendor\symfony\mime\Encoder\Base64MimeHeaderEncoder.php:17 Stack trace: #0 {main} thrown in D:\Apache24\www\qilu\back-end\vendor\symfony\mime\Encoder\Base64MimeHeaderEncoder.php on line 17