Warning: require_once(//admin.php): Failed to open stream: No such file or directory in /htdocs/admin.php on line 12

Fatal error: Uncaught Error: Failed opening required '//admin.php' (include_path='.:/usr/share/php') in /htdocs/admin.php:12 Stack trace: #0 /htdocs/index.php(11): require_once() #1 {main} thrown in /htdocs/admin.php on line 12