Why did a customer order an out of stock item on my site?

An order has just been received for an item that is out of stock.

How can this happen? We do not allow back orders. This is an existing customer, but an item they’ve never ordered before and doesn’t appear to be a recovered basket.

Hi - did you resolve this issue? I too have had this issue and I don’t have the boxed ticked to continue selling when sold out.