Deprecated: strtolower(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/html/lib/pkp/classes/core/PKPContainer.php on line 214

Fatal error: Uncaught Exception: Mailer driver isn't specified in the application's config in /var/www/html/lib/pkp/classes/core/PKPContainer.php:324 Stack trace: #0 /var/www/html/lib/pkp/classes/core/PKPContainer.php(275): PKP\core\PKPContainer::getDefaultMailer() #1 /var/www/html/lib/pkp/classes/core/PKPContainer.php(122): PKP\core\PKPContainer->loadConfiguration() #2 /var/www/html/lib/pkp/classes/core/PKPApplication.php(228): PKP\core\PKPContainer->registerConfiguredProviders() #3 /var/www/html/lib/pkp/classes/core/PKPApplication.php(200): PKP\core\PKPApplication->initializeLaravelContainer() #4 /var/www/html/classes/core/Application.php(50): PKP\core\PKPApplication->__construct() #5 /var/www/html/lib/pkp/includes/bootstrap.php(37): APP\core\Application->__construct() #6 /var/www/html/index.php(18): require_once('/var/www/html/l...') #7 {main} thrown in /var/www/html/lib/pkp/classes/core/PKPContainer.php on line 324