Fatal error: Uncaught Error: Class 'Postmark\PostmarkClientBase' not found in /home/app/htdocs/lidia/vendor/wildbit/postmark-php/src/Postmark/PostmarkAdminClient.php:13 Stack trace: #0 {main} thrown in /home/app/htdocs/lidia/vendor/wildbit/postmark-php/src/Postmark/PostmarkAdminClient.php on line 13