Warning: require_once(//core/App.php): Failed to open stream: No such file or directory in /htdocs/index.php on line 17

Fatal error: Uncaught Error: Failed opening required '//core/App.php' (include_path='.:/usr/share/php') in /htdocs/index.php:17 Stack trace: #0 {main} thrown in /htdocs/index.php on line 17