Fatal error: Uncaught Error: Class "Symfony\Component\Mailer\Envelope" not found in C:\www\Apache24\htdocs\agenda-dif\vendor\symfony\mailer\DelayedEnvelope.php:24 Stack trace: #0 {main} thrown in C:\www\Apache24\htdocs\agenda-dif\vendor\symfony\mailer\DelayedEnvelope.php on line 24