"Cancellation Rejected by the Order Management System" error

This article explains the "Cancellation Rejected by the Order Management System" message you may see in NinjaTrader, why the broker rejects a cancellation request, and what you can do to reduce how often it happens when copying trades with Replikanto.

What the message means

The message is generated by the broker's Order Management System (OMS), not by NinjaTrader and not by Replikanto. It appears when a request is made to cancel an order that was filled by the market microseconds after the cancellation message was received by the broker.

In other words: the order was already completed before the cancellation could be processed, so the broker rejects the cancellation and sends a rejection message back to NinjaTrader for display.

Why it happens

• When you attempt to cancel an order, especially one close to the bid/ask price, the market can move very rapidly.
• If the market fills the order before the broker processes the cancellation request, the broker sends a rejection message to NinjaTrader.
• Once an order is completed, it cannot be changed or cancelled. The rejection is the broker telling you exactly that.

When you are using a trade copier

With a trade copier such as Replikanto, cancelling or modifying an order on the leader account copies that action to the follower accounts. The time it takes for the request to travel to the follower's broker does not guarantee the order is cancelled or changed, because the follower order may be filled first.

That is why a cancellation you make on the leader account can produce a rejection message on a follower account: the corresponding follower order was already filled by the market before the cancellation request reached the broker.

How to reduce these rejections

1. Avoid attempting to cancel orders that are very close to the current bid/ask price.
2. Widen your stop orders.
3. Place orders a little further from the current bid/ask.
4. Avoid trading in high-volatility environments, where prices move fastest and fills happen soonest.

Protect the follower account with Follower Guard

Replikanto's Follower Guard can flatten the follower account automatically when a reject message is received from the broker, so a follower is not left holding a position the leader does not have.

Among the Follower Guard actions that can be enabled are:

• Flatten follower if any submitted order is rejected
• Flatten follower if it was unable to submit order
• Flatten follower if the cancellation order submitted returns in error

Right-click the Replikanto window > Properties... > Follower Guard. 1 = Disarm Followers, 2 = Flatten follower if any submitted order is rejected, 3 = Flatten follower if it was unable to submit order, 4 = Flatten follower if the cancellation order submitted returns in error, 5 = Flatten follower in the event of an error after X seconds. The large box holds all the order-error options.

Each of these actions comes into effect after the time you set, flattens the follower account, and — when the Disarm Followers option is checked — disarms the account and turns it red. For the full list of actions and how to configure them, see Follower Guard: Overview.

1 = Sim102 flattened and disarmed (red): it receives no new trades. 2 = Rearm turns the disarmed followers back on.

Important note

Market volatility is inherent, particularly in futures trading. Even when you try to cancel an order at a distance from the bid/ask, a sudden market movement may fill the order before the cancellation is processed. This message is therefore a normal market condition rather than a fault in NinjaTrader or Replikanto.