Fatal error: Uncaught Error: Class 'GUI' not found in /var/www/html/index.php:49 Stack trace: #0 /var/www/html/models/router.php(51): {closure}() #1 /var/www/html/index.php(57): Router::execute('/index.html') #2 {main} thrown in /var/www/html/index.php on line 49