Warning: require_once(./header.php): failed to open stream: No such file or directory in /home/customproxy/public_html/order_product.php on line 2

Fatal error: require_once(): Failed opening required './header.php' (include_path='.:/opt/cpanel/ea-php56/root/usr/share/pear') in /home/customproxy/public_html/order_product.php on line 2