In the Copy Settings, you can configure the copier status for a specific slav. It will define whether the copy trading is currently active or not. You can choose to copy all trades (ON), or copy only trades that open (Open Only) or close a position (Close Only), to deactivate the copy (OFF).
In such a case, you could receive a Deleted: Account is OFF/OpenOnly/CloseOnly order status if your master tries to place an order on such a slave on which you have defined a specific configuration.
Learn more about Copier Status: here.