order_total notice/issue

Hi,
I have notice about order_total: (just after checkout when redirecting to payment)
“Notice: order_total was called incorrectly. Order properties should not be accessed directly. Backtrace: require(‘wp-blog-header.php’), require_once(‘wp-includes/template-loader.php’), …”

in index.html you have order_total which is not available

could you fix this issue?