Fatal error: Uncaught Error: Interface "Psr\Container\ContainerInterface" not found in /var/www/html1/wp-content/plugins/zettle-pos-integration/src/Container/WpOptionContainer.php:13 Stack trace: #0 {main} thrown in /var/www/html1/wp-content/plugins/zettle-pos-integration/src/Container/WpOptionContainer.php on line 13