Warning: PHP Startup: failed to open stream: No such file or directory in /index.php on line 6

Warning: PHP Startup: failed to open stream: No such file or directory in /index.php on line 6

Fatal error: PHP Startup: Failed opening required '//../vendor/autoload.php' (include_path='.:/:/usr/local/php72/lib/pear') in /index.php on line 6