Fatal error: Uncaught Error: Class 'Symfony\Component\Mime\Encoder\Base64Encoder' not found in D:\workspaces\liZiPingBack\vendor\symfony\mime\Encoder\Base64MimeHeaderEncoder.php:17 Stack trace: #0 {main} thrown in D:\workspaces\liZiPingBack\vendor\symfony\mime\Encoder\Base64MimeHeaderEncoder.php on line 17