Can't mark orders as paid nopcommerce 3.70

Hi,
May you help me please. I want to mark orders as paid in my own plugin payment but I got this error

You can't mark this order as paid
Description: An unhandled exception occurred during the execution of the current web request

This is a part of my code

if (_orderProcessingService.CanMarkOrderAsPaid(order))
                {
                    order.PaymentStatus = PaymentStatus.Paid;
                    _orderService.UpdateOrder(order);

                    _orderProcessingService.MarkOrderAsPaid(order);
                }

I used the same code with nop 3.60 and worked well.

Need your helps
Thanks

If your "order" is not null then there is no reason not to execute the code.

The "order" is not null because the payment status is marked as "Paid" but when It comes to mark as paid, I receive an exception.
I don't understand the problem. The same code works in nop 3.60

Please try

if (_orderProcessingService.CanMarkOrderAsPaid(order))
            {
                _orderProcessingService.MarkOrderAsPaid(order);
                _orderService.UpdateOrder(order);

            }


And the order will show as admin panel as

Thanks Sina.Islam. Problem solved