What does "Order size exceeds the size limit" mean?

This message is a precautionary warning message that means the order size you have submitted is higher than what you have configured in your Precautionary Settings. The message allows you to double-check your order details and gives you the option to override the message and transmit the order. You can modify your Precautionary Settings within the Order Confirmation window by placing a check next to Change the limit to..., entering a new value, and clicking on the Update button.

You can also configure your Precautionary Settings in your Global Configuration.

Additional Information

Powered by IBot
TWS message: Order price is not reasonable or cannot verify reasonableness of order
What does "Order size not correct" mean?
How do I change the Precautionary Settings in IBKR Mobile?
What does the reject message "Order exceeds a percentage of the Average Daily Volume" mean?