CancelOrder() cannot cancel orders when Strategy starts

[localappleseed]

I am trying to test if the pre-existing pending buy orders can be canceled when Strategy starts.
Here is what I did:
(1) Manually submit a limited buy order through SuperDOM. This order is pending...
(2) Start Strategy() which includes the following code:
In OnStateChange():
Existing order can be found using
foreach (Order order in myAccount.Orders)
...
{
Print ("order =" + order); // it is confirmed this order is the correct pre-existing order
CancelOrder(order);
Print ("order =" + order); // nothing is printed here, so it looks like the order is canceled.
}
Later I can see this pre-existing order has not be cancelled. I also tried myCancelOrder = GetRealtimeOrder(order); it didn't work either. Adding the codes to OnBarUpdate() won't help.

Could you tell what I may have done incorrectly? What's the correct way to cancel this order?
Thanks in advance.

[NinjaTrader_ChelseaB]

Hello localappleseed,

CancelOrder() is a strategy method that can only cancel orders from the strategy.

Continue using the addon approach and use the Cancel() method from the account.

https://ninjatrader.com/support/helpGuides/nt8/cancel.htm

[localappleseed]

Hi, Chelsea,

Thanks for quick reply.
I re-tested a limit order submitted from Strategy, then stopped and re-started Strategy. CancelOrder() still cannot work. Thanks.

[NinjaTrader_ChelseaB]

Hello localappleseed,

The order would need to be submitted by the strategy while the strategy is running and the order is part of the strategy performance.

For the order to be resumed, the Immediately submit start behavior would need to be used and the order be matched, or the order will automatically be cancelled when the strategy instance is re-enabled.

https://ninjatrader.com/support/forum/forum/historical-beta-archive/version-8-beta/87750-load-cumulative-profit?p=783182#post783182