Processing constraints are not allowing to cancel sales order lines.

Hi Friends,

I have tried to cancel sales order line which is in Awaiting Shipping Status and getting following error message. ordered qty 1

Cancellation is not qualified at this point. Quantity "0" is not allowed

for a booked order if not cancellation. Please delete the line instead or

change the processing constraint setup to qualify the cancellation.

I have checked processing constraints rules and observed that there are 2 rules defined (Both same) for order line cancellation reasons. one is enabled and other is disabled.

If both rules are enabled, it is allowing me to cancel the sales order.

If deleted one duplicate rule/Disabled, it is not allowing me to cancel sales order.