Fatal error: Uncaught Error: Interface 'Composer\Plugin\PluginInterface' not found in /home/devmecseminars/public_html/mec/vendor/drupal/core-project-message/MessagePlugin.php:17 Stack trace: #0 {main} thrown in /home/devmecseminars/public_html/mec/vendor/drupal/core-project-message/MessagePlugin.php on line 17